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The effects of inclusive education on academic achievement for special education and general education students of color: a meta-analysis

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Content The Effects of Inclusive Education on Academic Achievement for Special Education
and General Education Students of Color: A Meta-Analysis
Katelynn J. Wright
Rossier School of Education
University of Southern California
A dissertation submitted to the faculty
in partial fulfillment of the requirements for the degree of
Doctor of Education
May 2024

© Copyright by Katelynn J. Wright 2024
All Rights Reserved

The Committee for Katelynn J. Wright certifies the approval of this Dissertation
Jacqueline Barry
Erika Patall, Committee Co-Chair
Adam Kho, Committee Co-Chair
Rossier School of Education
University of Southern California
2024

iv
Abstract
Inclusive teaching practices, sometimes known as mainstreaming or co/team teaching, are an
intervention that schools and districts use wherein special education students and general
education students are educated within the same general education classroom using general
education standards and curriculum for education. A research synthesis was conducted on the
effects of inclusive teaching practices (both mainstreaming and co/team teaching combined) on
academic achievement for K–12 students. Specifically for this synthesis, only studies where the
sample population was a minimum of at least 40% Black and/or Latinx students were used. A
meta-analysis of 33 samples from 11 inclusive teaching studies with a total of 62 effects revealed
a positive and statistically significant average effect on achievement (g = .2740). Variations in
effects emerged depending on the student grade level, percentages of Black and Latinx students
in the sample, and disability status of students. Overall, results highlighted the importance of
considering the grade level of students when deciding on inclusive teaching practices along with
the need for more research centering on types of co/team teach models and disability types when
making curricular decisions. Additional implications for theory, research, policy, and practice are
discussed.
Keywords: meta-analysis, research synthesis, mainstreaming, co-teaching, inclusivity,
student outcomes, achievement, K–12

v
Dedication
To my mom. You gave me everything I needed.

vi
Acknowledgements
I would like to thank my biggest supporter and champion, my husband, Matthew. I am
completely aware that I would not have been able to finish this undertaking without your daily
support. Thank you for literally picking me up off the floor (more than once) and reminding me
of why I took this all on. Sometimes I needed that reminder a hundred times in one day, and you
were always there to give it to me. I love you.
To my closest friends in education, Jackie and Jackie, your unwavering support of me
during all of this is so appreciated. Thank you for giving me a place to lean and empowering me.
I am grateful to know such intelligent women in education.
To my USC crew: Daryl, Joanne, Shannon, Maurissa, and Alia, our near-daily group
chats saved me more than once! We met this challenge with humor and passion, and I am so
thankful to have worked with you all for 3 years!
To my administrative team who planned around my insane schedule the past couple of
years, your understanding of my “I can’t work that day because I have class, or homework, or
class and homework” explanations was much appreciated.
To my bestie, Meighan, who had to continuously remind me that school is “my thing”
and that it always has been, so despite my craziness, I really could do it! Thank you!
To my dissertation committee, Erika, Adam, and Jacqueline, thank you for all your
feedback and positive affirmations. You kept me in the right headspace.
And to my mom who is no longer with me, I did this for you. You always wanted me to
write “the next great American novel,” but I think this is as close as we’re going to get!

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Table of Contents
Abstract.......................................................................................................................................... iv
Dedication....................................................................................................................................... v
Acknowledgements........................................................................................................................ vi
List of Tables ................................................................................................................................. ix
List of Figures................................................................................................................................. x
Review of the Prior Literature ............................................................................................ 4
The History and Purpose of Inclusive Education in the United States................... 4
Defining Inclusive and Non-Inclusive Educational Models/Terms........................ 9
Theoretical Foundations........................................................................................ 12
Theoretical Foundations in Support of Inclusive Education................................. 13
Theoretical Perspectives Against Inclusive Teaching Practices........................... 19
Review of Empirical Research Relevant to the Relationship ............................... 22
Factors Contributing to Variation in Relationships/Intervention Effects ............. 29
The Present Synthesis........................................................................................... 32
Methods............................................................................................................................. 34
Literature Search................................................................................................... 35
Inclusion Criteria .................................................................................................. 39
Data Extraction ..................................................................................................... 42
Computing Effect Sizes ........................................................................................ 44
Data Analysis........................................................................................................ 44
Results............................................................................................................................... 45
Overview of Dataset ............................................................................................. 45
Overall Average Effect of Inclusive Teaching ..................................................... 46
Publication Bias.................................................................................................... 47

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Moderator Analyses.............................................................................................. 48
Discussion......................................................................................................................... 51
Summary of Key Findings.................................................................................... 52
Alignment of Key Findings With Theory and Prior Research ............................. 53
Implications for Theory and Practice.................................................................... 56
Limitations and Recommendations for Future Research...................................... 58
Conclusions........................................................................................................... 61
References..................................................................................................................................... 63
Appendix A: Studies Used in Meta Analysis ............................................................................... 78
Appendix B: Coding Guide .......................................................................................................... 79

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List of Tables
Table 1: Overall Average Effect for Inclusive Teaching 46
Table 2: Publication Bias 48
Table 3: Moderator Analysis for Inclusive Teaching 49
Appendix A: Studies Used in Meta Analysis 78

x
List of Figures
Figure 1: Theoretical Foundations Supporting and Opposing Inclusion 14
Figure 2: PRISMA Chart 39

1
The Effects of Inclusive Education on Academic Achievement for Special Education and
General Education Students of Color: A Meta-Analysis
While the conversation surrounding how best to educate students with disabilities has
been most prevalent since the 1970s with the enactment of the Individuals with Disabilities Act
(IDEA) in 1975 (National Center for Education Statistics [NCES], 2021), school segregation
based on “ableism” can be connected to its predecessor of school segregation based on racism
that came to a head during the landmark case Brown v. Board of Education (1954)
approximately 20 years before. Both IDEA and Brown v. Board of Education fought to allow
students with differences, whether that be race or disability status, access to the same education
as all other students (Linton, 1998). Today, the topic of inclusive education continues to be a
source of discourse from educational researchers, policymakers including local boards of
education, parents, teachers, and district offices. The question remains, considering the laws
surrounding placing a student in their least restrictive environment and offering them Free and
Appropriate Public Education (FAPE), to what extent do students with disabilities who are
taught with classmates without disabilities achieve academically more or less than with only
similarly disabled peers in an environment that is created specifically for students with
disabilities (Szumski et al., 2017)? Similarly, the same question arises for students without
disabilities: to what extent (whether positive or negative) is their academic achievement
impacted by being taught in inclusive settings with students who have disabilities? In this study,
I took these questions and added the additional layer of looking specifically at studies that
included at least 40% of students who are Black and/or Latinx with and/or without disabilities
and the impacts that inclusion has on their academic achievement.

2
The purpose of this meta-analysis was to look at the impact on achievement that
inclusion has on Black and/or Latinx students with or without disabilities. While there have been
many studies done on both the positive and negative impacts of inclusive teaching practices on
students with and without disabilities, few studies focus specifically on the impact for Black
and/or Latinx students. This is surprising in the fact that students of color are overrepresented in
nine of the 13 disability categories, are the reason many school districts are labeled as
significantly disproportionate with their numbers and go into state monitoring systems, and are
more likely than their similarly disabled White peers to be placed in exclusionary educational
settings (Losen & Orfield, 2002). These facts alone would seem to favor more focused research
on minority students and inclusive education; however, research in this area is scant. Advocates
for inclusion lean on ethical and legal arguments that were implemented in the 1970s, while
opponents for inclusion cite a lack of empirical studies and research that show quality evidence
in support of the teaching style for both special education and general education students
(Szumski et al., 2017; Wang & Baker, 1986).
This meta-analysis is based on the existing research synthesized in John Hattie’s (2023)
Visible Learning overview meta-analysis and targets Hattie’s influences of
“mainstreaming/inclusion” and “co/team teaching” under the overall umbrella of inclusive
teaching practices, and, therefore, both influences are used together and interchangeably where
data are concerned. In this meta-analysis, I focused specifically on the empirical studies that
include at least 40% Black and/or Latinx students and were completed in the United States to
clearly articulate the effect of inclusive teaching practices on the achievements of
marginalized, and oftentimes overlooked, student populations.
The primary research questions this meta-analysis sought to answer were

3
1. What is the overall effect size of inclusion (both mainstreaming and co/team
teaching combined) on the academic achievement of K–12 Black and Latinx
students in the United States?
2. To what extent, if any, do the factors of race/ethnicity, age/grade level, and
disability status (special education students and general education students)
contribute to the variation in effects on academic achievement of inclusive teaching
practices for Black and Latinx students?
I begin this meta-analysis by offering some historical context and background
information about special education and inclusion history in the United States along with
specific definitions of inclusive and non-inclusive terminology. Next, I offer theoretical
foundations both in support and opposition of inclusive teaching practices. A review of
empirical research studies relevant to inclusive education and its impact on Black and/or Latinx
students follows, along with factors contributing to any variations among the relationships
found. Next, I describe the current synthesis, with specific explanation of the methods I used for
this meta-analysis, including the system for identifying literature, the inclusion criteria in the
study, the process for data extraction, and the analysis strategy. In the final sections, I will
review results via an overview of the dataset, the average effects of inclusion, any publication
bias among effects/correlations, potential moderators of effects, and finally a discussion of key
findings, implications for theory and practice, study limitations, and recommendations for future
research.

4
Review of the Prior Literature
The History and Purpose of Inclusive Education in the United States
Fourteen percent of all students in the United States between the ages of 3–22 receive
special education services under the Individuals with Disabilities Education Act (IDEA) in
school as recently as the 2019–2020 school year (NCES, 2021). IDEA, initially enacted in 1975,
mandates that students who are found eligible for special education services are entitled to a free
and appropriate public education (FAPE; NCES, 2021). Defining what constitutes a free and
appropriate public education, however, is a very individualized decision made by the student’s
individual education plan team, which includes teachers, service providers, school/district
administration, the student’s parents, and the student. IDEA mandates that free and appropriate
education is based on the idea of the student being served in their least restrictive environment
(Clayton et al., 2006), and courts have continued to uphold that a student can only receive a free
and appropriate education if they are positioned to obtain meaningful educational benefit in
schools (Wright & Wright, 2008), which can only happen if they are educated in their least
restrictive environments.
A student’s least restrictive environment means that, to the maximum extent possible and
appropriate, students with disabilities are educated alongside their non-disabled peers (EAHCA,
1975, sec. 1412; 5 [B]). Furthermore, the Education for All Handicapped Children Act (1975)
dictates that the removal of students with disabilities from the general education setting will
occur only when the nature of the disability is so severe that supplementary aids and services
written into an IEP cannot be achieved successfully in a general education classroom, and,
therefore, the student must be removed and placed in a special education setting with only
disabled peers. Historically, the definition of a student’s least restrictive environment has been

5
discussed and argued in court cases across the United States, since the definition of the term
“least” can be seen as subjective. The concept of least restrictive environment appears to have
been started in the 1970s with two major court cases, Pennsylvania Association for Retarded
Children (PARC) v. Commonwealth of Pennsylvania (1971) and Mills v. District of Columbia
Board of Education (1972; Crockett, 2014). Both cases sought to prove that children with
disabilities who were excluded from public schools and classrooms violated the equal protection
law under the 14th Amendment to the United States Constitution and that, as long as students
could receive educational benefits appropriate to their learning needs, they were entitled to be
educated in typical schools (Crockett, 2014). Coming out of cases like these, this approach of
situating disabled students among their non-disabled peers whenever possible was initially called
the least restrictive placement alternative (LRA), which came from the movement to relocate
adults and children from residences to state institutions, so the term, while very familiar to
lawyers, was much less familiar to educators (Crockett & Kauffmann, 1999). Some time later,
the word alternative was replaced by environment with the hopes of making the idea of location
less important and emphasizing the idea of educational services that could be provided within the
actual learning environments (Tucker, 1989). Clearly, special education laws have always
directed—and continue to direct—that students with disabilities must be educated with their nondisabled peers to the greatest extent possible so long as it is also appropriate to their educational
benefits (Turnbull, 2003). While many teachers support inclusive teaching models due to both
their legal understandings along with positive student impacts that are seen, many other teachers
feel inclusive teaching practices and models are not in the best interest of students (whether
special education or general education) due to ill-prepared teachers, a lack of rigor for the
students without disabilities, and social outcasting (Szumski et al., 2017; Wang & Baker, 1985).

6
Statistically speaking, approximately 50% of students with different disabilities spend
less than 40% of their time in general education/inclusive classrooms per day (U.S. Department
of Education, 2018). Reasons for this include students with severe disabilities needing to be in
specialized programs and schools for their health and safety or students with learning disabilities
needing to be in classrooms with smaller class sizes for more individualized support and more
modified curriculum. However, another reason includes teacher and district pushback when it
comes to inclusive teaching models to serve students in their least restrictive environments.
Despite the laws in place, there continue to be educators across many sites, in many states, who
feel legitimate reasons exist to keep special education students segregated in special day classes
(Kauffman et al., 2016). While there is research that inclusion negatively impacts the general
education, non-disabled students in the classroom (Akcamete & Gokbulut, 2018) both
academically and/or behaviorally, there is also research that shows that general education
students exhibit growth academically when they are educated in an inclusive setting (Cole et al.,
2004; Cushing & Kennedy, 1997). This suggests that, although many special education students
can show positive impacts academically in inclusive settings (Fisher & Meyer, 2002; Kurth &
Mastergeorge, 2010), non-disabled students also positively benefit from this environment.
Another common attitude shared by some general education teachers is they feel they do
not have the support or the capacity to teach such wide and varied populations of student needs
(Clayton et al., 2006; Fisher & Meyer, 2002; Ruppar et al., 2016; Volkmar et al., 2004).
Similarly, these teachers hold the idea that they did not go through the right types of school and
credentialing programs to teach students with special needs, and so the additional scaffolding,
accommodating, and modifying that may be needed to successfully support disabled peers in a
general education to reach positive academic achievement results is an unfair ask (Ruppar et al.,

7
2016). Regardless of how teachers may feel about inclusive teaching practices, whether that be
by full mainstreaming or co/team teaching, of special education students or general education
students into the general education setting, they must be consistently reminded that, legally,
students can only be removed from the general education environment if their services and
accommodations/modifications cannot be satisfactorily implemented in a way that allows them
access to the general education curriculum in the general education setting (Hosp & Rechly,
2003).
It is important to discuss the issue of inclusive education dependent upon the type of
disability a student has and the determination that needs to be made regarding whether inclusive
education is an appropriate choice for the least restrictive environment. While placing a student
with special needs in their least restrictive environment is the law, a student’s individualized
education plan team must determine specifically what that environment looks like. Children with
mild to moderate disabilities fall into the largest class of students with special needs and,
therefore, are the students most often included in inclusive teaching practices (Ruijs & Peetsma,
2009). Mild to moderate disabilities include disabilities that are most often recognized in schoolspecific areas such as learning disabilities in math or reading, auditory challenges, attention
deficit disorders, deaf/hard of hearing, or minor speech impairments in comparison with those
disabilities seen as more severe that impact not only academic and school performance, but also
life skills more typically seen with students who have severe autism, orthopedic impairments, or
intellectual disabilities like Down’s Syndrome (Vaughn, Schumm et al., 1998). Since students
with mild disabilities are more likely to “fit in” with general education peers, these students are
usually more encouraged through their individualized education plan teams to be placed into
inclusive settings, especially in core academic settings so they have access to core curriculum for

8
their academic growth (Ahmad, 2016; Vaughn, Elbaum et al., 1998), rather than mod/severe
students who would not see the same academic achievement in general education classes and,
instead, benefit from courses more focused on life skills (Block & Vogler, 1994). While the law
and rules of ethics point toward inclusive settings for students with disabilities, it remains
extremely important for a student’s team to determine the most appropriate least restrictive
environment where the student will thrive.
While special education law is not new in the field of education, it continues to be a
litigious subject when it comes to how it is viewed and implemented across schools in the United
States. Similarly, issues of race are at an all-time high, with the mandates of ethnic studies
classes in some states and the ties some feel it has to critical race theory; violence targeted
toward minorities not only in larger massacres, but also by police on the streets; continued
economic inequality; and disproportionate criminal incarceration rates. Given the fact that Black
and Latinx students are disproportionately labeled as having disabilities in most eligibilities and
placed in more restrictive environments (Ferri & Connor, 2005) across the country, more
research and studies must continue to be done looking into the academic impact that inclusive
teaching can have on Black and Latinx students with and without disabilities. The outcomes of
labeling students as special education cannot be ignored when it comes to White versus nonWhite students. Research shows that White students who are labeled as having a disability are
more likely to get accommodations for high-stakes tests such as Advanced Placement or the
SATs, general education maintenance, or access to extra support services, whereas Black and
Latinx students with the same labels are typically handed segregated, special education classes
as a means to solve their opportunity gaps (Parrish, 2002). While it is true that there is research
that shows either a negative impact or no impact at all on inclusive teaching practices for Black

9
and Latinx students, there is also research that shows the opposite, and, therefore, continued
studies and discussion surrounding inclusive education and its impact on achievement for
students of color are warranted.
Before a more in-depth discussion of how inclusion impacts students of color in the
United States, it is essential to define the different terms used in the educational system when it
comes to special education and general education teaching models.
Defining Inclusive and Non-Inclusive Educational Models/Terms
Mainstreaming
One of the most quoted and direct definitions of mainstreaming comes from Kaufman et
al. (1975) and explains it as “the temporal, instructional, and social integration of eligible
exceptional children with normal peers based on an ongoing, individually determined
educational planning and programming progress” (p. 3). A fully mainstream model means
special education students are in general education classrooms with their peers and being
instructed by a general education teacher who utilizes the students’ IEPs to support them in
accessing the curriculum.
Co/Team Teaching
Co-teaching is a model used to push forward the idea of mainstreaming for a student’s
least restrictive environment, but with some additional support. It can be defined as a model in
which special education teachers and general education teachers work together in one general
education classroom that accesses non-modified, grade-level curriculum and provides a variety
of instructional activities and supports in order to provide optimal instruction to the greatest
number of both disabled and non-disabled students together in one classroom (Reinbiller,
1996). It is not the same as full mainstreaming, as there is still a special education teacher in the

10
classroom to support special education students; however, special education students and
general education students are instructed together in a general education class working with
general education curriculum that has not been modified. Additionally, the special education
teacher in a co-teach classroom is never instructed not to also help general education students
when requested.
Inclusion/Inclusive Teaching Practices
For the purpose of this meta-analysis, inclusion (sometimes referred to as inclusive
teaching practices) refers to both co/team teaching and mainstreaming. The reason for this is
that, in many studies, the terms inclusion, mainstreaming, and co/team teaching are used
synonymously to describe general education classrooms that are taught by at least one general
education teacher who is using grade-level, general education curriculum to all students both
disabled and non-disabled in the classroom.
General Education Teachers and Classes
General education teachers and classes teach academic lessons and various skills that
students will need to attend college and to enter the job market (Bureau of Labor Statistics,
2021a). For the purpose of this paper, general education teachers refer to teachers who are not
specially credentialed to teach students with disabilities in the way that special education
teachers are. General education classes are those taught by general education teachers that meet
grade-level state standards and count toward a high school diploma (or advancement toward
high school for elementary and middle school) and meet college admissions requirements.
General education classes do not have a special education teacher who teaches alongside them.

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Special Education Teachers and Classes (Special Day Classes)
Special education teachers and classes work with students who have a wide range of
learning, mental, emotional, and physical disabilities (Bureau of Labor Statistics, 2021b). These
teachers must possess a special education credential and go through a different teacher
preparatory program that focuses on serving students with disabilities. Special education serves
students who qualify (through psychological and academic testing) via individualized education
plans that include services, accommodations, and modifications needed to best help the student
access academic curriculum. Special education classes do not count toward 4-year college
admissions but, in many cases, can count toward a high school diploma (or advancement
toward high school if elementary or middle school) if the class still follows the state-issued
standards. Special education follows the Individuals with Disabilities Act and aims to provide a
free and appropriate education to all disabled students.
Special day classes (SDCs), for the purpose of this paper, can be seen as the opposite of
an inclusive teaching model. Special day classes are self-contained classrooms instructed by
special education teachers and supported by various support personnel, most commonly being
instructional aides (Ball, 2021). Typically, SDC classes are located on a comprehensive school
site but can be separated from the main student body, although that is not always the case.
Students in special day classes may be there all day, or for part of the day, but generally are
there for at least 50% of the day (Ball, 2021). These classes may or may not follow state
standards. If they do, they can be considered diploma-track classes, but if they do not follow
the standards, then they count toward a certificate of completion in lieu of a diploma. SDCs do
not count for college admissions purposes. Additionally, there are never non-disabled peers in
SDC classes, as all students in SDC classes have an IEP.

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Special Education and General Education Students
For the purpose of this paper, a special education student is identified as a student ages 3–
18 (or the year in which the student completes his/her 4th year of high school) who has one of
the following disabilities, or a combination of the following disabilities: autism, deaf-blindness,
deafness, emotional disturbance, hearing impairment, intellectual disability, multiple disabilities,
orthopedic impairment, other health impairment, specific learning disability, speech or language
impairment, traumatic brain injury, or visual impairment (IDEA, 2004, Sec. 300.8). For the
purpose of this paper, general education students are considered to be ages 3–18 (or the age in
which a student graduates from high school) who do not have an individualized education plan.
This does not mean, however, that the student does not have a disability, but instead that their
disability does not affect their educational progress enough to qualify for special education
supports and services.
Theoretical Foundations
Examining theoretical foundations allows researchers and readers to explore
different ideas through a lens that can either distort or focus what is seen. Theoretical
perspectives are imperative in research, because they organize thoughts and ideas and make
them clear to readers. For this research synthesis on inclusive teaching practices, the
graphic in Figure 1 represents the different theoretical foundations that both support and
oppose the idea of inclusion and its impact on academic achievement. While examining the
different theories and their connections to inclusive teaching, an important area of note is
that the theories more clearly reflect and explain potential impacts on special education
students. This is most likely because inclusive teaching is a major change in placement for
special education students, while there is nowhere near as substantial of a difference for

13
general education students. When looking at special education students and their potential
placement, having them learn in a setting with students who are all disabled and study
modified curricula versus a setting where the majority of students are non-disabled and
studying grade-level curricula yields a much more dynamic change for the disabled student,
as non-disabled students would be learning surrounded by their non-disabled peers with
grade-level curricula regardless, with perhaps a small addition of disabled peers in a
primarily non-disabled student classroom. That is not to say that no positive or negative
impacts could occur for general education students, just that it would be expected that there
would be a far less significant impact one way or the other.
Theoretical Foundations in Support of Inclusive Education
Learning theories such as cognitive learning theory, constructivist learning theory,
and intersectionality theory support the idea of inclusive teaching. When thinking about
inclusive education, it is especially important to consider the key classroom learning
strategies and focuses that each theory supports so teachers can make the correct teaching
strategy and curriculum decisions for their students in inclusive settings. The entire goal of
inclusive education is to allow for all students, regardless of disability status, to receive full
access to the academic curriculum that will allow students to achieve at the highest level,
just as the goal of education in general is to support all students in their academic
achievement along with social growth.

14
Figure 1
Theoretical Foundations Supporting and Opposing Inclusion
Cognitive Learning Theory
Cognitive learning theory centers on the characteristics of one’s self-reflection, memory,
thinking, and learning motivation (Al-Shammari et al., 2019). When looking at cognitivism, the
emphasis is not just on gaining knowledge, but instead on making it meaningful and relatable to
a learner’s everyday life by relating it to what they already know through reflection and memory,
which allows them to achieve academically at higher levels (Petersen, 2014). Because of this

15
focus, cognitivist instruction starts with a student’s existing mental structure and experiences and
continues to build from there (Ertmer & Newby, 2013). Teaching practices such as outlining,
framing, summarizing, concept mapping, journaling, and writing reflective pieces are all seen in
cognitivist-based general education classrooms because they allow students to connect their prior
experiences and knowledge to new concepts they are learning in class; these strategies are also
proven to directly support students with special education needs (West et al., 1991). When
thinking about individual education plans for students with special needs, the key word is
individual. These plans take what the team knows about a student (e.g., cognitive scores, areas of
strength and weakness, health backgrounds) and use the information to create an individual plan
that includes services, accommodations, and modifications to help the student succeed in the
school setting, whether in general education or special education classes. The same principle is
found in cognitivism insofar as it focuses on what the student already knows to facilitate the best
processes and strategies to teach them new concepts (Tunmer et al., 2002). Students with special
needs who are seated in inclusive settings that use practices with roots in cognitive learning
theory are able to see what their non-disabled peers may personally relate to and understand and
learn from their experiences as well as their own experiences. By placing special education
students in non-inclusive settings, they are cemented in knowledge that only they themselves
have, along with students who have very similar experiences and knowledge, instead of allowing
them to learn from the experiences of their non-disabled peers as well. Similarly, it is not just
special education students who can benefit from diverse perspectives within the classroom
setting. While special education students can learn from their non-disabled peers both
academically and socially, general education students can also subtly benefit socially from being
with their disabled peers within the classroom setting as they witness the grit and determination

16
that students with disability may have to put forth to access general education curricula, which
could potentially translate to eventual small achievement effects for general education students
too.
Cognitivist strategies utilized in inclusive classrooms such as framing, using graphic
organizers to see connections to real-world experiences, and writing reflective pieces allow
students with disabilities to not only learn through their own reflections and experiences, but also
see how their non-disabled peers interact with the world around them. Allowing students with
disabilities to be a part of classrooms where non-disabled peers discuss and summarize how
academics connect to their everyday lives allows them to show students with disabilities
different ways to connect academics to learning, thus improving their academic achievement
through the cognitivist lens.
Constructivist Learning Theory
The theory of constructivism focuses on a person understanding the social experiences
and insights of their culture that impacts their learning process (Al-Shammari et al., 2019).
Constructivism says that the key to student learning is when the instruction is learner centered,
hands-on, and task based (Shi, 2013). This is strikingly similar to the goal of individualized
educational plans, which put the student at the center of their learning and help guide teachers
to understand how best to structure tasks for disabled students so they can learn optimally.
Higher-level depth of knowledge teaching strategies that can be seen in general
education classrooms include teaching with real-life examples and tasks (such as performance
tasks), modeling, coaching, peer tutoring, cooperative learning, debates, summarizing, and
paraphrasing (Ertmer & Newby, 2013; Hattie, 2008). And while all these strategies have also
been found to have positive achievement effects on students with special needs (Hattie, 2008),

17
they are far less common in special education classes that focus more on rote memorization and
teacher-centered instruction instead of student-centered activities that include high levels of
engagement and peer interaction more typically found in general education classrooms (Seo et
al., 2008). Therefore, creating inclusive teaching environments that utilize constructivist
strategies that are interactive and allow students to learn from one another in a social setting are
a benefit to all students involved, especially students with special needs who benefit greatly
from modeling of their non-disabled peers in mainstream settings. In a study conducted by
Botha and Kourkoutas (2016), students with social-emotional and behavioral difficulties
(SEBD) were traced to see what instructional and academic practices best support them in the
learning environment. The study found that students who have social-emotional and behavioral
difficulties (for which special education may qualify under OHI or ED) more easily develop
antisocial behavior when they feel excluded from people and places (such as exclusionary
teaching practices like remediated classes), and, therefore, an inclusive teaching environment
that values constructivist strategies like peer tutoring and cooperative learning allows them to
feel more connected to school, teachers, and peers and make the most of their education,
greatly positively impacting their academic achievement (Botha & Kourkoutas, 2016). In an
inclusive classroom environment that utilizes constructivist teaching strategies and practices,
students are able to learn from their own experiences (and those similar to them) in addition to
the experiences of their non-disabled peers as well who have had different life experiences than
their own. This positively impacts academic achievement for students with disabilities as they
are able to work together with non-disabled peers to problem solve situations or tasks that can
be solved in a variety of ways.

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Intersectionality Theory
Intersectionality theory was first developed by Kimberlé Crenshaw in the 1980s to
describe the overlapping discrimination that women who were also African American had to
live through in America (Crenshaw, 1989). Crenshaw described the lack of help antidiscrimination legislation provided for African American females due to forcing females to
choose between either their race or gender despite the intersection between them (Crenshaw,
1989). This theory has now started to lend itself to inclusive teaching practices as well (Bešić,
2020). The overall learnings from intersectionality teach us that a person’s identity, and the
ways in which others discriminate against certain people’s identities, cannot be observed
separately (Cooper et al., 2016). For example, a student’s disability is one part of their identity,
but a disabled student can also be African American or Latinx, and that is also a part of their
identity that cannot be separated from their disability. Essentially, before truly knowing a
person, every identity marker that makes a person up (their race, their ability, their gender, etc.)
must be recognized as being connected in making up that person’s full identity (Crenshaw,
1990).
With this theory in mind, inclusive teaching practices represent the ability for an
organizational response to the entire student instead of just a part of them. By using
intersectionality in the educational realm, interactions between diversely abled peers are
celebrated for what students with different strengths can bring to the classroom. It forces
schools to look at all the pieces that make up a student, including their disabilities, and give
them opportunities to be among different students with different levels in the same way that the
end of school segregation forced students of different races to learn among one another. Grant
and Zwier (2011) argue that the application of intersectionality in the educational sphere

19
enables the examination of concurrent interactions involving various factors such as gender,
dis(ability), migrant background, race, and class for each individual child. It also encompasses
the dynamic interplay between these individual or group characteristics. In sum, using
intersectionality as a basis for inclusive education allows educators to respond to the entire
student instead of just responding to their disability by placing them in a special day class. This
theory underscores the idea that marginalized or discriminated-against students frequently
encounter various overlapping forms of marginalization and discrimination, both at the
individual and institutional levels. These effects contribute to the social and educational
stratification that educators for both inclusive education and culturally relevant pedagogy and
practices aim to address. However, such educators often find themselves trapped in such
differentiation because they overlook the interconnected nature of these effects when
formulating and implementing inclusive education policies (Hancock, 2007).
Theoretical Perspectives Against Inclusive Teaching Practices
While there are many data points and theories in support of inclusive teaching practices,
it is important to note that not all theories are supportive of such practices due to the increased
social and academic pressure that it puts on special education students and the idea that
teaching to the lowest denominator (students with disabilities both academic and behavioral)
could hold higher-achieving general education students back academically (Berryman, 1989).
Both social cognitive theory (and, specifically within this theory, the big fish little pond effect)
and cognitive load theory do not support inclusive teaching practices.
Social Cognitive Theory (The Big Fish Little Pond Effect)
Albert Bandura first introduced his cognitive learning theory in the 1970s and described
it as the influence that the actions of others, individual experiences, and environmental factors

20
have on an individual’s self-efficacy and their own behaviors (Alsarawi & Sukontheman, 2021).
Essentially, one’s life experiences are directly impacted by both the people and places
(environment) that surround him/her. Academic learning primarily takes place in a school
setting for the majority of students under the age of 18. The settings of school sites themselves
are social settings where students from different backgrounds, cultures, and different academic
prowess interact with one another in said social setting. Due to the social interactive nature of
the school setting, the big fish little pond effect (BFLPE) has a direct impact on students with
disabilities who are educated in inclusive settings. There is vast research that suggests students
with disabilities who are educated in homogeneous classrooms (also known as special day
classes or remedial classrooms) hold higher academic self-concept (and thus achieve higher
academically) than those disabled students who are educated in inclusive settings (Dai & Rinn,
2008). In a study conducted by Marsh and Hau (2003), the researchers found that the academic
self-concept of special education students decreased when they were moved to inclusive
classrooms and educated alongside their non-disabled peers. However, when the same students
were moved from inclusive settings into special schools or classrooms, their academic selfconcept actually increased instead, and thus their academic achievement and positive attitudes
about academics increased as well. Students with disabilities are oftentimes in tune with the
students who surround them in their general education classroom settings when it comes to
being able to tell when students do and do not need any academic assistance. When general
education students are able to achieve academically with little support from the teacher, students
with disabilities in the same classroom who need extra support but see their peers outscoring
them may begin to shy away from tasks as their academic self-concept decreases (Dai & Rinn,
2008). Often, this negatively impacts their academic achievement, as they will give up on

21
assignments or tests and get lower grades overall. In special day classes where special education
students are grouped with peers who have more similar academic prowess, academic risk-taking
becomes a positive experience for special education students when they do not feel the pressure
from seeing general education peers outperform them consistently, which positively impacts
their achievement as risk-taking leads to more assignment completion and a willingness to
engage in higher-level academic activities (Dai & Rinn, 2008).
Cognitive Load Theory
Kennedy and Romig (2021) explain cognitive load theory as humans having limited
capacity at any given time, or in any given place, to use their various inputs (visual, tactile, or
auditory) to take in new information and place it into long-term memory storage. Therefore,
when a person has reached their mental capacity because their cognitive capacity is
overwhelmed, learning cannot occur. Cognitive load theory suggests that cognitive load must be
limited so students can have additional mental capacity to learn. Opponents of inclusive
teaching practices argue that instruction for students with disabilities must be designed and
implemented in a way that cognitive overload does not occur. Inclusivity opponents believe that
strategies, language, and tools needed to learn for these students are more available to them in
special day settings and not in inclusive settings where disabled students can easily become
overwhelmed by curricula too difficult for them (Feldon et al., 2019). Alloway et al. (2009)
offer the idea that students with specific learning disabilities already have impaired cognitive
functionality, and, because of this, their ability to learn content in a faster-paced environment
with less help from a teacher may manifest in a variety of ways, such as lack of memory for a
test or the ability to organize thoughts for an essay, which all result in learning being more
difficult for the student. Due to students with disabilities often starting with impaired cognition

22
when compared to their non-disabled peers, it can be more difficult for disabled students to learn
in an environment with fewer supports than a special education classroom. Researchers and
teachers alike will use cognitive load theory as a theory to support the homogeneous grouping of
students with and without disabilities in separate classrooms.
Similarly, we also see cognitive load theory take effect with classroom teachers trying to
manage a large spread of different learning capabilities within the same classroom. In general
education classrooms with both special education students and general education students,
teachers are responsible for the academic achievement of all students; however, that is often
very difficult for teachers who have to create different strategies and assessments for such a
diverse student population (Clayton et al., 2006; Fisher & Meyer, 2002; Ruppar et al., 2016;
Volkmar et al., 2004). This can in turn lead to the negative impact on general education student
academic achievement (Akcamete & Gokbulut, 2018). It takes a lot of extra time and effort for
teachers to really create lessons and learning strategies that both fill in potential gaps for special
education students while also allowing for the expansion of knowledge for general education
students who may be more academically inclined. Just as disabled students can feel
overwhelmed with the academics required of them in general education classrooms, teachers
can also feel overwhelmed with the time and creativity needed to put lessons and learning
opportunities together for such a vast array of diverse student needs, which, unfortunately, can
end up leading to less-than-stellar academic extension opportunities for general education
students if the classroom teacher is only able to teach to the “middle” student.
Review of Empirical Research Relevant to the Relationship
There is significant research that exists on both the positive and negative impacts of
inclusive education on students from elementary school through high school. Most early

23
studies focus on the impact of inclusion on students with disabilities, most likely due to the
legal ramifications of the 1970s when protections were put into place insisting that students
with disabilities have fair access to general education curricula and peers. More recently, there
has been significant research done on the impact of inclusion on general education students as
well instead of only focusing on students with disabilities. However, there continues to be a
lack of both past and present research that discusses how inclusion affects both general
education and special education students of color. This literature review aimed to focus
specifically on studies and connections made between inclusive teaching environments and
their impact on African American and Latinx students by focusing primarily on empirical
research that utilizes sample populations of at least 40% or more minority (African American
and Latinx) students.
The positive impacts on achievement for African American and Latinx students
through inclusive teaching practices cannot be ignored. Many studies show that, for both
special education students and general education students, growth associated with academic
areas is evident (Cawley et al., 2002; Goulburn, 2017; Grimaldi, 2009; Harrison, 2011; Kluwin
& Moores, 1985; Osborne et al., 1991; Owoh, 2013; Spence, 2022; Vaughn et al., 1996).
When looking at studies that focus on the academic growth of students with and without
disabilities within inclusive environments, it is important to point out that the studies used all
focus on students with mild to moderate disabilities and not students with moderate to severe
disabilities. This is because students with disabilities who are placed in core, academic subjects
for inclusion are focused on gaining access to college preparatory curriculum and not on the
life skills needed by students with moderate to severe disabilities (Vaughn, Elbaum et al.,
1998).

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Utilizing Inclusion to Achieve Academically for All Students
Most of the empirical research that centers on the positives for inclusion looks at
academic areas, primarily math and reading achievement. Owoh (2013) conducted a study with a
sample of 52 African American elementary students (Grades 3–5) in Washington, DC, that
showed statistically significant gains for special education students in inclusive math classes on
standardized tests. A similar study conducted in New Jersey looked at 141 special education high
school students who were all African American or Latinx. Those in inclusive math settings
performed slightly better than those in special education settings (Spence, 2022). A similar study
in New York utilized a sample of 57% African American and Latinx students who were in fifth
and sixth grade, and those numbers revealed a statistically significant increase in math
achievement scores for male students (Grimaldi, 2009). Positive impacts of inclusion are not
only reserved for special education students. Additional research shows that general education
students also show growth academically when in an inclusive setting (Cole et al., 2004; Cushing
& Kennedy, 1997). An example of this occurred in a study conducted in Indiana that explored
inclusive school settings at six different schools and revealed that non-disabled students who
were educated in inclusive classrooms with their disabled peers made significantly greater
progress in reading and mathematics than non-disabled students who were educated in typical
general education classes with only similarly abled peers (Cole et al., 2004). Similarly, in a study
conducted by Cushing and Kennedy (1997), general education students in a suburban
intermediate school of approximately 1,100 students from culturally, economically, and
ethnically diverse backgrounds were studied when acting as peer supporters in general education
classrooms with varying disabilities. In this study, students without disabilities who were
identified by their teachers as having less academic engagement with class activities than their

25
peers and who were willing to work with disabled students were able to participate in the study.
Baseline data were taken by teachers on these specific students using homework completion
rates, class participation, and time on task before being paired with their disabled peers. At the
end of the experiment, Cushing and Kennedy (1997) found that these cooperative learning
arrangements provided positive academic and social benefits for all general education students
involved. Specific areas of note in this were improved academic growth for the non-disabled
students who participated in the areas of academic engagement (time on task), assignment
completion, grades, and classroom participation in addition to social growth when it comes to
empathy.
The Social Benefits on Academic Achievement Within Inclusive Settings
Direct academic achievement measured through grades, participation, and test scores is
not the only measure of achievement when it comes to education. Research indicates that
students who maintain positive relationships with their teachers and other students along with
increased engagement and positive views of self are more likely to do well in school
academically (Fisher & Meyer, 2002; Kurth & Mastergeorge, 2010). So, while this specific
analysis focuses on the academic achievement of minority students in inclusive settings, it is
important to recognize that academic achievement is highly connected to social aspects as well.
Fisher and Meyer (2002) implemented a study in which 40 special education students were
assessed over a 2-year period in both inclusive and self-contained classroom settings looking at
their child development when it came to social competence and independent behaviors. The
inclusive group made statistically significant gains in both areas as compared to the selfcontained group of students. In a parallel manner, Cawley et al. (2002) describe a study in
which there were 114 students (64% of whom were African American or Latinx), some with

26
learning disabilities and emotional disabilities, from an inner-city neighborhood middle school
that had a much higher acceptance rate socially between general education students and special
education students after the inclusive experiment in their science classes started. In this study,
teachers noted that, once the inclusion classes were formed, general education students and
special education students were seen attending dances together and participating in typical
social conversations at much higher intervals than before, when the special education students
were segregated in their special education science class. In a similar fashion, the same study by
Cawley et al. (2002) detailed the fact that there were significantly fewer discipline referrals of
general education students in the inclusion classes than in the pure general education classes,
which allowed for more students to stay in class and learn content rather than be pulled from
class to engage in punitive discipline.
Allowing students with disabilities to be educated alongside their non-disabled peers
potentially improves their self-esteem, which then becomes a springboard for positive effects
academically as students feel they are able to achieve at the same rate as the peers around them
in their classroom (Ntshangase et al., 2008). Research shows it is more than reasonable to
believe that students who have positive feelings about their classes due to friendships they have
made or social competence they have gained are more likely to be motivated and give
maximum effort on assignments, thus increasing academic achievement (Lamport et al., 2012).
The positive impact of inclusive teaching practices on the academic and social development of
students, including those with and without disabilities, is evident in numerous aspects.
Challenges and Drawbacks of Inclusive Teaching
Despite the positive benefits for both special education and general education students
in inclusive classroom settings, there is also much empirical research that suggests inclusive

27
teaching practices may not always be what is in the best interest of students with and without
disabilities, especially minority students. A study executed in Texas examined seventh grade
inclusive and non-inclusive math classes in which 57% of the sample were African American
or Latinx students (Belmarez, 1998). The study indicated that students with disabilities in the
inclusive classes showed a slight increase in raw math standardized test scores but showed
significantly lower growth over the year and in grade averages as well. In this same study, nondisabled students in inclusive versus non-inclusive classes did not show any statistically
significant differences. This presents a valid argument for inclusion opponents in that not all
students benefit from being in a general education classroom alongside students with
disabilities, whether that be non-disabled students or disabled students; sometimes the general
education class cannot serve all students appropriately. In another study, an urban school
district looked at 10th grade science and social science classroom settings for 4,275 students,
48.8% of whom were African American or Latinx students (Neugebauer, 2008). In this study,
with all student races combined, general education students revealed statistically significant
losses in academic test scores and grades in inclusive settings. For African American and
Latinx students, there was no difference between those who participated in general education
classes versus inclusive classes.
While research exists on the positive social benefits inclusion has on students and the
positive impact those benefits have on academic achievement, there is also research that
highlights the detrimental effects of inclusive practices on students through negative social
consequences (Freeman & Alkin, 2000; Goodman, 1971; Gottlieb, 1981; Margalit & Efrati,
1996; Wiener et al., 1990). These consequences can arise due to different factors, including the
potential for negative peer interactions or stigmatization. One of the primary negative social

28
consequences of inclusive teaching is the possibility of negative peer interactions, as students
with learning disabilities in inclusive settings are sometimes rejected by their non-disabled
peers (Wiener et al., 1990). In a diverse classroom, students may come from different cultural,
socioeconomic, or linguistic backgrounds, and students who are also disabled in their general
education classrooms often have to contend with having a lower social status than that of their
non-disabled classmates (Goodman, 1971). Unfortunately, this diversity can sometimes lead to
misunderstandings, stereotypes, and even bullying. Students who feel different from their peers
or are struggling academically may become targets of teasing, exclusion, or discrimination
(Gottlieb, 1981). These negative social interactions can have a detrimental impact on the
emotional well-being of students, which, in turn, leads to negative academic achievement
impacts, because students who are struggling emotionally have a difficult time achieving
academically. When students’ self-confidence is damaged, their motivation to achieve declines,
leading to an overall lowering of academic performance, as it can hinder their ability to fully
engage in the learning process.
The Role of the Teacher in Inclusive Teaching
Another important factor to look at when considering inclusive and non-inclusive
educational setting impacts is the classroom teachers themselves. While many teachers are in
favor of inclusive teaching practices due to the empirical evidence that suggests that it works
well for students, along with the fact that it is simply the law, other teachers are not in favor
of inclusive teaching for a variety of different reasons (Center & Ward, 1987; Forlin et al.,
1996), those reasons stemming from the belief of teachers that it could negatively impact the
general education students in the classroom (Akcamete & Gokbulut, 2018). Additionally,
there is the idea that teachers feel they do not have the support or capacity to teach to such

29
wide and varied student needs (Clayton et al., 2006; Fisher & Meyer, 2002; Ruppar et al.,
2016; Volkmar et al., 2004). In a study that explored students in kindergarten through 12th
grade with 60 students total (55% of whom were African American or Latinx) who had
learning disabilities, findings were mixed in their support of inclusive education when it came
to special education student and general education teacher interactions in the classroom, per
results from classroom climate scales (McIntosh et al., 1993). In this study, the special
education students were found to engage less when it came to asking questions or
volunteering answers when in general education classes versus special education classes.
The 2018 United States Supreme Court case of Endrew F. v. Douglas County School
District mandated that students who fall under IDEA have the right to ambitious educational
programs that are appropriate and have the potential to challenge them and offer opportunities
for growth (Wehmeyer et al., 2017). Students who receive special education services cannot
and should not all be treated the same by putting them in special day classes surrounded only
by peers who have the same disabilities. Similarly, research also shows that placing all
students with disabilities into general education classes may not automatically be what is best
for them either. In addition to considering special education students and their educational
rights, it is also important to consider the research that shows the impacts (both positive and
negative) of general education students in inclusive environments.
Factors Contributing to Variation in Relationships/Intervention Effects
It can sometimes be difficult to define inclusive education because there are so many
different versions of it that range from full mainstreaming of students with IEPs in general
education classes with no support through students with severe disabilities who have one-to-one
aides who accompany them to general education classrooms. Around the time when IDEA first

30
came into the educational systems, parents were dissatisfied with their disabled students’
educations and defined a student’s least restrictive environment as being educated in general
education classrooms (Ferri & Connor, 2005). However, as more schools started building their
educational programs to meet the idea of a free and appropriate education for disabled students
for legal reasons, both advocates and supporters of inclusive education found the results lacking
in depth and substance (Nealon, 1991, as cited in Ferri & Connor, 2005, p. 467). Today, students
with and without disabilities along with their families and teachers are at a crossroads with
inclusive teaching practices. While there are plenty of studies that support inclusion for all
students, there seem to exist the same amount of data that show the opposite. To understand why
some studies support inclusion while others do not, it is important to consider the different
factors that characterize most studies on inclusion.
Characteristics of the Sample: Race/Ethnicity
Studies show that minority students, especially Black students, are more than two times
as likely as their White counterparts to be labeled as emotionally disturbed or intellectually
disabled (Parrish, 2002), which are two of the qualifying disabilities that are most frequently
found to be kept isolated in special education classes instead of inclusive classrooms (Fierros &
Conroy, 2002). Unfortunately, this means that many studies on inclusive education do not
account for many African American or Latinx students because those students are typically not
included in general education classrooms. When looking at inclusive studies that do have higher
numbers of Black students (60% or more in samples), the overall numbers to support inclusion
for special education students tend to be higher than studies where Black student sample
numbers are lower (Carter & Hughes, 2013). However, there is not much research available on
how general education Black students are affected by inclusion or how Latinx students (both

31
special education and general education) are affected by inclusion, whether positively or
negatively. Therefore, this meta-analysis utilized percent of the sample that is Black and Latinx
as a moderator.
Characteristics of the Sample: Age/Grade Level
The age of students and the grade level they are in may also impact the outcomes of
studies on inclusive education for students both with and without disabilities. There are more
positive outcomes of inclusion for students with and without disabilities at the elementary level.
For students with disabilities, this may be because younger students are more accepting of
differences during this time, and so the social opportunities are better, thus creating better
chances at higher achievement in the class (Stevens & Slavin, 1995). For students without
disabilities, they may have more opportunities to ask for individual help from teachers or aides,
and they may see more varied teaching strategies that are no longer common post–elementary
school due to a focus on content knowledge over instructional strategies at the middle school
and high school levels in general education, college-prep classes (Boe et al., 2007; Szumski et
al., 2017). Additionally, it is important to recognize the structural differences in elementary
school from middle and high schools that could play into variation effects. High school general
education teachers are trained to deliver content knowledge to their students at the highest levels
(Boe et al., 2007), and they only see the students for an hour a day. Special education teachers
(and students), on the other hand, are more used to the teacher/student bond that special
education classes typically have due to the students being with the same teacher and classmates
for multiple hours a day, which would be difficult for students with disabilities to be
comfortable with when mainstreamed into a totally different structure (De Vroey et al., 2016).

32
Characteristics of the Sample: Disability Status
As discussed numerous times already in this synthesis, research on inclusive teaching
practices and its impact on academic performance and achievement for students differs
depending on whether the student is disabled or non-disabled. Most research that centers on
positive outcomes for inclusive teaching spotlights positive academic achievement outcomes for
students who are disabled, while focusing more on positive social outcomes (in lieu of academic
achievement) for students who are non-disabled. This meta-analysis aimed to look specifically at
only academic achievement for both disabled and non-disabled students when the sample is at
least 40% Black and/or Latinx to see if inclusivity positively or negatively impacts academic
achievement markers such as standardized test scores and letter grade for both types of students.
The Present Synthesis
Inclusion offers opportunities for both disabled and non-disabled students to achieve
higher both academically and socially due, in part, to offering students opportunities to interact
with peers that they would not be able to interact with if separated into different environments.
Students can learn from the different backgrounds of one another and gain insight into how
different students with different abilities interface with curriculum, instruction, and different
social situations, which all impact their achievement in the classroom. However, there is also
significant research that shows the opposite, wherein disabled and non-disabled students
perform lower academically and have negative social interactions when put into inclusive
classrooms. While many studies and meta-analyses explore the effects of inclusion on student
achievement, there is scant focus on inclusivity’s effects on minority students, specifically.
This synthesis utilized only studies that have at least 40% African American and/or Latinx

33
student outcomes in order to analyze to what extent inclusion directly impacts students of color
and their academic achievement.
This meta-analysis sought to answer questions regarding the effect size of inclusion
(both mainstreaming and co-teaching combined) on the academic achievement of K–12 Black
and Latinx students both with and without disabilities. My hypothesis for the overall effect size
for students was that the effect size will be small, but positive in regard to inclusive education
and its impact on academic achievement. This is due primarily to the fact that, in Hattie’s
(2023) original meta-analysis for co/team teaching, he found an overall effect size of 0.19,
which he categorized as likely to have a positive, although small, impact. Similarly, in the
same meta-analysis, Hattie (2023) also found mainstreaming to have a positive effect size of
0.25, which is larger, but still relatively small when looking at effect sizes; however, any
positive effect can be meaningful.
Additionally, this meta-analysis sought to discover the extent, if any, of how factors
relating to race/ethnicity, age/grade level, and disability status contribute to the variation in
effects on academic achievement of inclusive teaching practices for Black and/or Latinx
students. I hypothesized the factor of race/ethnicity would have no relationship with the size of
the effect of inclusive teaching on achievement. That is, I did not expect that the percent of the
sample that is Black or Latinx would be associated with the effect of inclusion. While I did
hypothesize that the effect on Black and Latinx students would be positive overall, I did not
expect it to be any more positive than the overall predicted positive effect size for all students
within the sample, thus the null hypothesis. This is because there is not much research on how
inclusive education affects Black and Latinx students, whether they are disabled or nondisabled, so it would be difficult to make a hypothesis predicting a negative or positive result.

34
For the age/grade-level moderator, I predicted that the effect of inclusion would be positive
when looking at elementary-aged students and null when looking at secondary-aged students
with a statistically significant difference between them. Research shows that students in
elementary school are more likely to be accepting of peers who are different from them
socially than in middle school and high school due to the formation of cliques among students
who are similar to them as they get older (Gifford-Smith & Brownell, 2003), so, therefore,
students with disabilities feel more accepted in elementary school versus middle or high
school, which is proven to have positive effects on academic achievement (Wischnowski et al.,
2004). Lastly, I hypothesized that disability status would moderate the effect of inclusion on
achievement for students such that inclusivity would have a positive effect on the academic
achievement of disabled students and there would be no meaningful impact (positive or
negative) on the academic achievement of non-disabled students (with a statistically significant
difference between the groups) due to the fact that the majority of research suggests that
academic achievement of inclusivity is primarily seen for disabled students while social and
behavioral impacts are more seen for non-disabled students rather than academic achievement.
There was little research that directly discussed the academic achievement outcome of
inclusive teaching practices for non-disabled students.
Methods
This meta-analysis was based on Hattie’s (2023) book Visible Learning, in which he
analyzed over 130,000 studies encompassed within 2,100 meta-analyses. The purpose of Hattie’s
work was to determine to what extent over 320 individual influences affected student
achievement. This synthesis focused specifically on two of Hattie’s (2023) influences—
“mainstreaming/inclusion” and “co/team teaching”—and their effect on K–12 Black and Latinx

35
students. While completing the literature search, it became apparent that many of the studies
under both influences used the terms “co/team teaching,” “mainstreaming,” and “inclusion”
interchangeably, along with other research used for the review of literature outside of Hattie
using the same terminology, and, therefore, it was decided that I would combine studies from
“mainstreaming/inclusion” and “co/team teaching” together under the umbrella of inclusive
teaching or inclusive teaching practices. For this synthesis, I began by screening all available
studies from Hattie (2023) on mainstreaming/inclusion and co/team teaching to see if they met
the initial inclusion criteria, which were taking place in the United States and having a sample of
at least 40% Black and/or Latinx students. Once the initial screening was complete, I revised my
research questions based on the initial information in the studies. Next, I completed the literature
search to serve as additional research and background information for Hattie’s (2023) included
studies. After the literature search was complete, data extraction occurred for all selected studies
using a coding guide that I created to extract the appropriate information out of each study,
including effect sizes to answer my research questions. Once the data extraction was finished, I
assessed and synthesized the data, which involved summarizing key findings, identifying
patterns and trends, and organizing the data using statistical methods in order to determine the
overall effect that inclusion has on the achievement of Black and/or Latinx students.
Literature Search
The studies in this meta-analysis were all included in Hattie’s (2023) meta-analysis on
influences that directly support student learning. Studies for this meta-analysis were taken from
the Visible Learning website under the influences of “mainstreaming/inclusion” and “co/team
teaching.” Visible Learning indicated 244 studies within nine meta-analyses under
mainstreaming/inclusion and 136 studies within two meta-analyses under “co/team teaching” for

36
a total of 380 studies. Both “co/team teaching” meta-analyses as listed by Hattie (2023) were
located using the USC Library database; however, upon close inspection, one of those metaanalyses that Hattie used actually used seven other meta-analyses to get the studies that they
were said to have been composed of. Two of those seven major meta-analyses could not be
located by any databases, nor by USC librarians or interlibrary loans, which left the studies
shorter in number by 51 (27 studies from one of the meta-analyses that could not be located and
24 from the other that could not be located). With all the other studies I was able to locate, there
were 19 duplicate studies from within the meta-analyses and 64 studies that did not meet the
inclusion criteria. In sum, 66 non-duplicated studies were able to be found for the influence of
“co/team teaching,” and, out of those 66 studies, only one met the inclusion criteria. Many of the
studies that could not be used were due to them falling outside the United States or having less
than 40% African American or Latinx students included in the sample. Of the nine metaanalyses included by Hattie (2023) for “mainstreaming/inclusion,” seven were able to be located
using USC’s database. Ultimately, one meta-analysis (Kavale & Carlberg, 1980) was omitted
due to the meta-analysis not including the studies used or a references page for the metaanalysis, which took away 50 studies from the overall number of 244 included in Hattie’s (2023)
project. The other omitted meta-analysis (Zumeta, 2009), which accounted for nine studies,
could not be located, and after contacting the author directly, she said that work had never been
published and therefore she was unsure as to how Hattie could have referenced it.
Another item of note for the literature search is that the Dixon and Marsh (1997) metaanalysis is labeled by Hattie (2023) as being comprised of 70 studies; however, after studying
the meta-analysis very closely, it is clear that the authors directly say they only used 12 studies
for their publication, which they also list in a table, so while Hattie (2023) accounted for 70

37
studies in that meta-analysis in his total, there were really only 12 used studies, which subtracted
the true total of studies used by another 58 studies. Additionally, 13 studies were duplicates and
99 studies did not fit the inclusion criteria. Therefore, of the 244 studies cited by Hattie (2023)
for Visible Learning’s influence of “mainstreaming/inclusion,” 127 studies were able to be
located through the existing meta-analyses and online databases and used in this literature
search, and, of those studies, 16 fit the inclusion criteria for mainstreaming. In sum, for the
entire literature search for this meta-analysis, 180 non-duplicated studies were able to be located
out of 380 for both influences. The duplicate study number was 32. In addition, 160 studies were
unable to be located, and there was an error of 70 studies being quoted as being used, but it was
only 12 studies that were used, bringing down the total another 58 studies.
During the search and study analysis process, it became apparent that there were
multiple discrepancies between the number of studies Hattie indicated and the number of studies
that were actually used in the meta-analyses. This was revealed by looking at reference pages
and counting direct studies cited and comparing them to Visible Learning. Additionally, there
were approximately 40 studies overall between both influences that were duplicates within
different meta-analyses. Therefore, out of a possible 322 true studies (which accounts for the
error previously described, making it 322 studies and not 380) between the two influences,
about 66% of the studies total could be located due to full meta-analyses being unavailable,
studies within the meta-analyses not being cited, or studies being impossible to locate through
various search means. The included PRISMA chart (Figure 2) notates the different reasons
studies and meta-analyses were not included. When looking at the final study exclusions, it is
noted that one study was not codable due to not using identified special education students but,
instead, just students who were poor readers. Another four studies were not included as those

38
studies did not define general education and special education in the same way that my study
did. These studies looked at students’ classroom placement in non-public schools in which
100% of the students are special education, so there were no general education students to
compare them to. One study was a “within-subjects” design, again, without comparable general
education students.
For most of the study search process, Google Scholar was applied, as it can easily be
linked to a USC library account and can therefore search the USC library database and the
internet at the same time. For studies that could not be found using Google Scholar or the USC
database, ProQuest Dissertation & Theses Full Text, ERIC, and PsychINFO were also
explored. When none of these searching techniques worked, the librarian chat feature on the
USC website was employed and was able to be used to connect directly with USC librarians,
who, in many cases, helped in the search for studies. Lastly, in some instances, the USC
librarians directed the search toward the Interlibrary Loan and Document Delivery (ILL)
feature, where some of the outstanding studies were able to be obtained, either online or by
hard copy mail. All meta-analyses and studies that were able to be located were coded using a
very brief Google coding sheet to determine if the study could be found and if it met the
inclusion criteria. If it met the inclusion criteria, a copy of the study was hyperlinked in the
sheet and placed into a Google Drive folder for further investigation and use.

39
Figure 2
PRISMA Chart
Inclusion Criteria
The inclusion criteria for this meta-analysis included the following: the study sample
was located in the United States, included at least 40% African American or Latinx students,

40
and the students were in grades K–12. This information was typically found in the methods
section of the study under “sample” or “population.” Seventeen total studies initially met these
inclusion criteria, but later throughout the coding process, it was reduced to 11 studies total for
this synthesis due to studies not being codable because of their design and/or studies not
meeting the final inclusion criteria because the definition of inclusion did not match how I
defined inclusion for this meta-analysis.
Inclusive teaching practices were operationalized to include any form of
mainstreaming, co-teaching, or team teaching. In these operations, general education students
(non-disabled) and special education students (with mild to moderate disabilities) are educated
in core academic subjects (English, math, science, or social science for grades 6 through 12) or
general classes for elementary school (grades K–5) in general education classes, meaning a
general education teacher is present for the entirety of the school day (elementary school) or
class period (middle and high school). General education classes subscribe to the individual
state’s grade-level standards, and curriculum is not modified for special education students,
although it can be accommodated. In sum, inclusion for this meta-analysis is operationalized as
a teaching model that combines the definitions of co/team teaching and mainstreaming, as both
co/team teaching and mainstreaming take both special education and general education
students and educate them together in a general education setting. The only difference between
mainstreaming and co/team teaching is that, in the team-teaching model, both a special
education and general education teacher are present. However, this is still considered inclusive
teaching, as students are taught together in the general education setting.
Academic achievement was operationalized by using both standardized and nonstandardized testing along with letter grade percentages on report cards and overall GPAs.

41
Some examples of standardized and outcomes measured used were the Texas Assessment of
Academic Skills (TAAS), the Texas Assessment of Knowledge and Skills (TAKS; Belmarez,
1998), the New York State Math and English Language Arts Assessments (Grimaldi, 2009)
and the Stanford Achievement Test Hearing Impaired Version (SATHI; Kluwin & Moores,
1985). Non-standardized tests used to measure academic achievement outcomes were
primarily composed of pre and post tests and class projects and activities (Cawley et al.,
2002). Of the five different design types (descriptive, correlational, quasi-experimental,
randomized control trials/experiments, single-group experimental), the type of designs that
were utilized for this study were primarily quasi-experimental, although there was at least one
true experiment (RCT) included as the included studies attempted to establish a cause-andeffect relationship among the influence of inclusion and its effect on the academic
achievement of Black and/or Latinx students. Because all screened-in studies were already
experimental, no studies needed to be screened out due to type, and this also matched the
literature in general, where the vast majority of studies were quasi-experimental.
Studies that were not included in this meta-analysis include any studies that were not
initially used in Hattie’s (2023) Visible Learning project along with any studies that were not
quasi-experimental or true experimental (RCT) designs. Additionally, studies that focused on
teacher outcomes were not included in this study. Studies present in Hattie’s (2023) Visible
Learning project that were conducted in the United States and had a student sample of at least
40% Black and/or Latinx students were included in this synthesis. Studies that focused on the
academic achievement outcomes of special education students and non-disabled students
were included if the study utilized any inclusive teaching practices during the experiment and
tracked the outcome on achievement for any student group.

42
Data Extraction
A team of graduate researchers from the University of Southern California and I
extracted a wide range of information from studies that met our inclusion criteria. As part of a
larger project to resynthesize all of Hattie’s (2023) influences, this meta-analysis utilized a
coding guide, which can be found in full detail under Appendix A. The coding guide comprised
various elements pertaining to meta-analysis characteristics, report characteristics, sample and
participant characteristics, outcome measures, research design, predictor influences, and effect
size calculation.
The meta-analysis from which the study came is found in the meta-analysis
characteristics. Report characteristics that were coded include the publication type, data sources,
year(s) of data collection, and whether the report employs an overlapping data set. Setting
characteristics to be coded included the study’s location by state (if given), region, classroom
type (general education or special education), and school level. Participant and sample
characteristics to be coded included information on whether the sample was analyzed overall, as
a subgroup, or both, percentages of race and ethnic groups, grade level, gender, and other
common demographic data for schools like economically disadvantaged percentages and
English learner percentages. As this meta-analysis focused specifically on the influence of
inclusion, other sample information included type of disability for disabled students and student
type (either disabled or non-disabled).
Influence and predictor measures that were coded included the influence definition in the
report and how the researcher manipulated the influence. Additionally, the type of inclusive
teaching practice (whether mainstream or co-teach), the number of special education students in
the classroom, and type of co-teach model used were coded to assess possible moderators.

43
Outcome measures that were coded included the types of outcomes (e.g., state standardized tests
or GPA), outcome descriptions, domain of the outcome, unit of analysis, timing of the influence,
and whether the data collection was simultaneous or longitudinal. Research design and effect
size codes that were coded included the sample size, the direction of the relationship between
the influence and the outcome, and the type of research design. As the design type for these
studies was experiments, the number of participants in the treatment and control groups was
found along with the mean for the outcome variable for the treatment and control groups and the
standard deviations for both groups as well. Once these numbers were found, I calculated the
effect size. For studies that separated outcomes for special education students and general
education students, I calculated different effect sizes for moderator analyses. This was done by
using my coding guide to mark whether the experimental group (which was always the inclusive
teaching classroom[s]) was using students who were in special education or general education,
which allowed me to calculate the moderator analyses and see effect sizes for those groups
within studies separately. Ultimately, the overall effect size for both types of students combined
was reported and analyzed, and then samples that differentiated between both student types were
able to be used for moderator analyses.
Accurate and consistent coding is extremely important in a meta-analysis. With this in
mind, I underwent approximately 2 months of weekly practice coding sessions with additional
coders led by professors who are considered experts in their field. During this period, we
practiced coding individually, in pairs, and as a group, checking our solutions as a team. After
the expert coding leaders believed we had practiced enough, all coders were given a formative
assessment of coding, and if we got 80% correct for solutions, we were able to begin coding
independently. Over a period of several months, I coded my studies independently while they

44
were validated by another graduate student coder. As discrepancies (or errors) arose, the other
coder and I met to discuss the errors and reached an agreement. The error rate for this metaanalysis was about 30%. There were no situations in which an error agreement was not easily
met.
Computing Effect Sizes
Effect magnitudes were determined for studies examining interventions by using
standardized mean differences (SMD) in academic achievement between the treatment group
(inclusion intervention) and the control group. The effect sizes were directly computed using the
mean values, standard deviations, and sample sizes of both the intervention and control groups
whenever feasible. If students were exposed to multiple treatment conditions compared to a
single control condition, the effect size was calculated separately for each intervention
condition. Subsequently, intervention effect sizes were converted to bias-corrected Hedge’s g, a
standardized effect size that accounts for a slight positive bias typically observed in effects with
small sample sizes (Hedges, 1981).
Data Analysis
The intervention data underwent meta-analysis using the metafor and clubSandwich R
packages (Pustejovsky, 2019; Viechtbauer, 2010). Random-effects modeling was employed
throughout the analyses. To address the interdependence among effect size estimates within
studies and mitigate the risk of model misspecification, a multilevel modeling approach was
adopted in conjunction with a robust variance estimator (Pustejovsky & Tipton, 2022). A
random-effects model was utilized to estimate the aggregated effect size for the association
between inclusion and academic achievement. Furthermore, the presence of heterogeneity

45
among effect sizes was also evaluated using Q, τ2, and I2 statistics. The weighted average effect
is reported with a 95% confidence interval (CI; Borenstein et al., 2011).
To delve deeper into the heterogeneity observed in the effect size estimates, mixedeffects meta-regression models were employed. Each moderator’s impact was examined in
separate models. The specific moderators that were investigated included grade level, the
percentage of Black and/or Latinx students, and student disability status. Lastly, the potential for
publication bias and funnel plot asymmetry was explored by conducting an Egger’s regression
test (Egger et al., 1997) and analyzing publication status as a moderator in a meta-regression
model.
Results
Overview of Dataset
A total of 11 studies, 62 effect sizes, and 32 samples were identified for use in this study
(five published and six unpublished). Within these studies, eight studies came from secondaryaged students (Grades 6–12), two came from elementary-aged students (Grades K–5), and one
study combined elementary and secondary, so it was not used for a moderator analysis. All
studies used the intervention of inclusive education being either mainstream education (one
general education teacher in the room with special education and general education students) or
co/team teaching (one general education and one special education in the room with special
education and general education students in the room). While all 11 studies that were used came
from Hattie’s mainstreaming influence, the mainstreaming influence studies he used were
primarily co/team teaching by definition, even though he did not label them that way. From the
11 total studies, eight of them used co/team teaching as the experimental group and three of them
used actual mainstreaming for the experimental group. The total sample size included 5,376

46
students for the overall reported effect size. This comprised 4,524 general education students and
852 special education students. All studies occurred between the years 1985 and 2013. The
authors, sample sizes, and effect sizes for these studies can be found in Appendix A.
Overall Average Effect of Inclusive Teaching
The overall average effect for inclusive teaching on the academic achievement of
students with study samples of at least 40% Black and/or Latinx was positive and statistically
significant (g = .2740, p < .001). This is in line with the hypothesis that the overall average
effect would be small, but positive, which was based on Hattie’s (2023) effect sizes of
mainstreaming (g = 0.25) and co/team teaching (g = 0.19). It should be noted that this effect
size, which only included samples that were at least 40% Black or Latinx and completed in the
United States, was slightly larger than both of Hattie’s original effect sizes for mainstreaming
and co/team teaching that did not take into account race specifically or location.
Table 1
Overall Average Effect for Inclusive Teaching
95% CI
Outcome Nstud Nsamp NES g Low/Hi Tau2 I2 Q
Achievement 11 32 62 .2740*** 0.0887/0.
4585
0.105
6
87.61 439.18***
Note. *p < 0.05, **p < 0.01, ***p < 0.001.

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Publication Bias
Publication bias seeks to explain to what extent published and unpublished studies or
missing data influence results and to what extent results would change if the analysis procedure
were changed. Published studies (n = 5) were considered peer-reviewed journals, chapters, and
books. Unpublished studies (n = 6) were master’s theses and/or doctoral dissertations. To look at
publication bias for this meta-analysis, I performed a publication bias moderator test along with
an Egger’s test. The results from the modified Egger’s regression model suggested there was no
evidence of funnel plot symmetry for the intervention dataset (b = .37, SE = .26), t(60) = 1.42,
p = .16). However, the moderator analysis comparing published and unpublished reports
indicated that the pooled intervention effect did statistically significantly differ by publication
status for academic achievement (see Table 2). This means that results should be read with
caution given that the number of published and unpublished studies was nearly even, but the
effects were very different, and, in addition to this, the effect size of unpublished studies was
essentially zero. When studies with significant results are more likely to be published than nonsignificant findings, it can lead to an overinflation of effects. In this study, the five published
studies had significantly higher effect size than the six unpublished studies. Additionally, it is
important to note that, when a test for outliers was performed, no outliers were found in the data
set.

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Table 2
Publication Bias
95% CI
Moderator Nstud Nsamp NES b(SE) g Low/Hi
Publication bias
Published 5 20 62 – .448 0.155/0.7403***
Unpublished 6 13 62 –0.402(0.162)** 0.046 –.1332/0.225
Note. *p < 0.05, **p < 0.01, ***p < 0.001.
Moderator Analyses
Three moderators were looked at for this analysis: age/grade level (elementary and
secondary), race/ethnicity (the percent of Black and Latinx students in the sample), and disability
status (special education students and general education students). The prediction for age/grade
level was that elementary students (Grades K–5) would have a positive effect and secondary
students (Grades 6–12) would have no effect (positive or negative) with a statistically significant
difference between them. My hypothesis for race/ethnicity was that the percent of the sample
that is Black or Latinx would not be associated with any effects. For the disability status
moderator, I predicted a positive effect size for disabled students and no effect (positive or
negative) for non-disabled students with a statistically significant difference between them.
Results and discussion for each moderator can be found in Table 3 and discussion points below.

49
Table 3
Moderator Analysis for Inclusive Teaching
95% CI
Moderator Nstud Nsamp NES b(SE) g Low/Hi
School level
Elementary 2 13 13 – 0.519** 0.2187/0.8188
Secondary 8 19 47 –.382(.176)* 0.138 –0.0953/0.370
% Black sample 11 31 60 .011(.003)* –0.052 –0.268/0.164
% Latinx sample 11 31 60 –.009(.004)* 0.542* 0.290/0.793
Disability status
Special ed. 8 20 32 – 0.554*** 0.316/0.792
General ed. 7 11 28 –.669(.137)* –0.115 –0.290/0.060
Note. *p < 0.05, **p < 0.01, ***p < 0.001.
Moderator 1: Grade Level/Age of the Sample
Elementary-aged student samples included grade levels kindergarten through fifth grade.
Secondary-aged student samples included grade levels of sixth grade through 12th grade. A total
of 60 effect sizes within 10 studies were considered for this moderator analysis. Results of this
meta-analysis show a positive effect size of g = 0.519 for elementary students, which was
statistically significant (SE = 0.137, CI = 0.2187/0.8188). For secondary students, an effect size
of g = 0.138 was found, but it was not statistically significant (SE = 0.111, CI = –0.0953/0.370).
Secondary students have an effect size that is –0.382 lower than elementary students for the
intervention of inclusive education on academic achievement with samples of at least 40% Black
and/or Latinx students. This difference between the effect sizes by grade level was statistically
significant, as the confidence intervals do not include zero (CI = –0.748 low, –0.016 high).
Overall, my prediction was correct, as the hypothesis was that the effect size would be positive

50
for elementary school and null for secondary with a statistically significant difference between
the two.
Moderator 2: Percent of Black and Latinx Student Sample
In this meta-analysis, only studies with at least 40% Black and/or Latinx students were
used. For the race/ethnicity moderator, the intercept was the average effect between inclusive
education and achievement when the sample is 0% Black for the Black moderator analysis and
0% Latinx for the Latinx moderator analysis. When the sample was 0% Black, the intercept was
g = –0.052 and was not statistically significant; when the sample was 0% Latinx, the intercept
was g = 0.542, and that number is statistically significant based on the intercept’s confidence
intervals of 0.290/0.793. In contrast to my hypotheses, results showed that, for every 1% the
sample increased in the percentage of Black students, there was a .011 positive change in the
effect between inclusive education and academic achievement. This change in effect was
statistically significant based on the confidence intervals (CI = 0.0033, low and 0.0181, high).
For the Latinx moderator, for every 1% increase in the percentage of Latinx students in the
sample, there was a –0.009 change in the effect between inclusive education and academic
achievement. This was also statistically significant based on the confidence interval (CI =
–0.0187, low, –0.0002, high). Overall, the effect of inclusive education was statistically
significantly positively associated as the percent of the Black student sample increased
(g = 0.011), while the effect size was statistically significantly negatively associated with the
percent of the sample that was Latinx students (g = –0.009). These findings suggest that
inclusive education may be particularly effective for Black students but may be less effective or
even ineffective for Latinx students.

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Moderator 3: Student Sample Disability Status
This moderator analysis looked at disability status for students both in their difference in
effect sizes and also independent effect sizes. The data show that general education students have
an effect size of g = –0.669 lower than disabled students, which is statistically significant given
the confidence intervals (CI = –0.951, low and –0.386, high). Independently, the effect size for
general education, non-disabled students was g = –0.115 with a CI of –0.29 (low) and 0.06
(high), which is not statistically significant. The effect size for special education students was
g = 0.554 with a CI of 0.316 (low) and 0.792 (high), which was statistically significant. My
predictions were supported, as I predicted a positive effect for disabled students and a null effect
size for general education students with a statistically significant difference between the two.
Discussion
The purpose of this meta-analysis was to analyze how the effect sizes of Hattie’s (2023)
Visible Learning influences of co/team teaching and mainstreaming may differ for Black and
Latinx students in the United States. Only studies that were completed in the United States and
had a sample of at least 40% Black and/or Latinx were initially included in this study. Once the
initial screening was complete, studies underwent additional screening to make sure they were
experimental or quasi-experimental, fit under the categories of co/team teaching and/or
mainstreaming, and used research methodology wherein an effect size could be calculated. In
Hattie’s (2023) meta-analysis, he reported 380 total studies for mainstreaming and co/team
teaching, 4,831,149 students, and 572 total effects. This meta-analysis pared down Hattie’s
research to 11 studies, 5,376 students, and 62 total effects.

52
Summary of Key Findings
The first research question for this meta-analysis asked what the overall effect size of
inclusive teaching practices was for all students in the samples screened in (where every sample
had at least 40% Black and/or Latinx students). I found the overall average effect to be both
positive and statistically significant at g = .2740. This was in line with my prediction that the
overall effect size would be small, but positive. Referring back to Hattie’s (2023) effect size
results for mainstreaming (g = 0.25) and co/team teaching (g = 0.19) where race and location
were not taken into account, this effect size is meaningful insofar as it is slightly larger than
Hattie’s findings, leading to the belief that inclusive education may be particularly effective for
some minority students, given the Latinx finding, within the United States. However, it is
important to also remember that, when looking at publication bias, the unpublished studies (n =
6) had an effect size equal to zero, and, therefore, interpretations of results should be met with
caution.
The second research question looked more closely at possible reasons why effect sizes
could differ. Specifically, the moderators that were analyzed were age/grade level, race/ethnicity,
and student disability status (either non-disabled or disabled students). The overall effect size for
elementary students (K–5) was g = 0.5194, which was statistically significant and positive, and
the effect size for secondary students (6–12) was 0.1375, which was not statistically significant.
This was in line with my hypothesis. For the race/ethnicity moderator, I looked at Black students
and Latinx students separately. In sum, the effect of inclusive education is statistically
significantly more positive for samples with a greater percentage of Black students, while the
effect size for Latinx students is significantly less positive. While my prediction for Black
students was correct (an effect size that was small, but increasingly positive), my prediction for

53
Latinx students was incorrect, as I hypothesized that there would be more positive effects for
Latinx students as well, and the effect decreases with a greater percentage of Latino students,
though it is not statistically significant and therefore cannot be looked at as different than zero.
Lastly, the disability status moderator found that inclusive teaching had an effect size of g =
–0.12 for general education students and an effect size of g = 0.55 for special education students.
My predictions for disabled students and special education students were supported, as I
predicted a positive effect size for special education students and no effect (null) for general
education students with a statistically significant difference between them.
Alignment of Key Findings With Theory and Prior Research
My overall findings are primarily in line with prior research. Hattie’s 2023 Visible
Learning found small but positive effects for both mainstreaming and co/team teaching similar to
my overall finding of a small but positive effect size as well. In addition to this, it is important to
remember that the Individuals with Disabilities Education Act (IDEA), which was enacted in
1975, was built on the premise that students learn best in their least restrictive environments,
which, for disabled students, would be in general education classrooms. Therefore, a positive
effect size for students in mainstreaming or co/team teaching general education classes supports
the original purpose of IDEA.
Research shows mostly positive effects for inclusion when it comes to elementary-aged
students (Stevens & Slavin, 1995), which is also in line with this study and my hypothesis.
Additionally, there is mixed research when it comes to the outcome of inclusive education for
non-disabled students. While some research shows positive effects due to students having more
opportunities to ask for help (Szumski et al., 2017), other research shows that non-disabled
students show academic losses in inclusive settings, especially in core subjects (Neugebauer,

54
2008). However, other research also shows the positive social and behavioral aspects of
inclusion on non-disabled students, which many people believe can lead to positive academic
outcomes as well (Cawley et al., 2002). The race/ethnicity numbers for Black students did align
with prior research that suggested that, when Black, disabled sample numbers are higher, those
students achieve academically higher (Carter & Hughes, 2013), as results from this meta-analysis
show that, for every 1% the sample goes up for the percentage of Black students in the sample,
there is a .011 positive change in the effect between inclusive education and academic
achievement. As the percentage of disabled, Black students in the sample grew, the effect size
also grew positively. However, when it came to Latinx students, there is very little research on
how inclusive teaching affects their academic performance, and, in this meta-analysis, as the
number of Latinx students in the samples increased, the effect size decreased. As Guiberson
(2009) explains, there is definitely a need at both the national and state levels for more studies
that focus specifically on the patterns and trends of special education and Latinx students,
because, with the few studies that do exist, the sample sizes are small, so information is difficult
to analyze. Both Black and Latinx students are minority students, so it is important to consider
why inclusive education seems to work better for one than it does the other. Currently, there is an
overrepresentation of both Black and Latinx students in special education, particularly in states
such as California and Texas (Meyer & Patton, 2001; Ortiz & Yates, 1983). For Latinx students,
studies have shown that, for a majority of students who get labeled as special education students,
it is not because they have a disability, but, rather, because of cultural differences and linguistic
needs (Wilkinson et al., 2006). This could help to explain why we see a declining effect size for
Latinx students as their sample size increases when it comes to inclusion, seeing as special
education services focus on disabilities when what they most need may be linguistic support

55
(such as English learner strategies) or culturally responsive teaching practices, which an IEP
does not necessarily guarantee or focus on. While Black students are also often overrepresented
in special education, it is typically not because of linguistic differences. Typical, remedial special
education programs traditionally lack the rigorous curriculum and pedagogy that students need to
develop their skills (Codrington & Fairchild, 2012); however, inclusion allows students access to
general education curriculum and pedagogy that Black students may benefit from. Black students
are less likely to be exited from special education than their White peers (Blanchett, 2006), so if
they are designated as special education students, at least within an inclusive setting, they are
learning from rigorous curricula and therefore can possibly achieve at higher levels
academically, or at least achieve at the same level they would have without inclusion. It is clear
that additional studies and research need to be focused on the effects of inclusion on minority
students and what works best for them along with reasons certain practices work better than
others.
The majority of research surrounding inclusive teaching and disability student status
points to positive academic achievement outcomes for students who are disabled (Owoh, 2013)
and more on positive social outcomes such as positive behavioral changes (in lieu of academic
achievement) for students who are non-disabled (Fisher & Meyer, 2002). This was in line with
my study, as the overall effect size for disabled students was positive, but the overall effect size
for non-disabled students was not significantly different from zero when looking at just
academics. Given that this meta-analysis focused only on academic achievement and not social
outcomes, this is representative of a lot of research, since there isn’t much research that supports
positive academic outcomes for general education students. In the literature that does exist
regarding the impact of inclusion on general education students, studies note that, typically, low-

56
achieving general education students benefit from inclusivity while higher-achieving students
may lose ground (Huber et al., 2001; Semmel & Gerber, 1990). This could explain this paper’s
findings of a null effect on general education students’ academics given the student levels in
classes being mixed between higher-achieving general education students and lower-achieving
general education students balancing one another out to an overall non-statistically significant
effect. In addition to this, general education students’ placement is not changed with inclusivity,
as they are still learning general education curricula at the same rate, whereas special education
students’ placement is drastically changed in inclusive settings with higher rigor in demand.
Implications for Theory and Practice
When looking at inclusive teaching practices and theory, it is important to remember the
overall goal of inclusive teaching is that every student gets what they need to be successful
academically and socially. A large part of disabled student achievement is giving them access to
their non-disabled peers so they can see connections to real-world experiences that they may not
experience themselves but that their non-disabled peers do. Cognitivist strategies focus on
reflective strategies like this, and this meta-analysis shows that, for disabled students, inclusive
education does indeed help them achieve academically. This is similar to what we learn from
intersectionality theory, which argues that inclusive teaching provides an opportunity for an
organizational response to students who are different and need to learn from others who surround
them. Instead of only responding to a student for being disabled, intersectionality theory teaches
us that schools should be looking at the student as a whole and what they bring to the table. The
positive effect size as a whole for inclusive education shows this is true.
While the results of this meta-analysis definitely replicate some of the theoretical ideas
previously discussed here, two areas where there is a mismatch are in the area of social cognitive

57
theory—more specifically, in the big fish, little pond effect—and in cognitive load theory. In
both theories, we are told that disabled students may not perform as well in general education
classes because they would compare themselves to the higher-achieving general education
students (Dai & Rinn, 2008) or become overwhelmed by the expectations placed upon them in
classrooms that work with general education standards and move at a faster pace (Feldon et al.,
2019). However, with a positive effect size for disabled peers from this study, it would seem to
show that disabled peers do in fact perform well and can rise to the challenge in general
education classrooms.
When looking at how this study informs the practice of professionals in the education
field, it is necessary to consider the teacher(s) themselves and the preparation they are given to
both teach in an inclusive setting as well as handle the culture differences of minority students
and what they need to be successful. Both general education and special education teachers must
be equipped and trained to be successful in an inclusive setting. For co/team teaching, training
must be provided on how to teach together, co-teach instructional strategies, and understand the
way students on IEPs learn. In addition to this, administrators who oversee the master schedule
must take into consideration a schedule that allows for joint planning and collaboration time. As
co-teaching becomes more and more popular among districts across the country (Dieker &
Murawski, 2003), credentialing programs also must consider the need to highlight and train on
this in their preparatory programs.
This meta-analysis focused specifically on studies with a student sample of at least 40%
Black and/or Latinx students, and, therefore, the importance of educators understanding the need
for cultural awareness as they teach minority students cannot go unsaid. For disabled students
who are also Black or Latinx, their identities are oftentimes twisted up in an educational system

58
that does not adequately support them. Even for minority students who are not disabled, the
educational system does not adequately address their cultural needs. Studies are consistent with
their research about the constant mismatches between teacher perceptions of education and
academic achievement in comparison to their Black and Latinx students’ perceptions (Mahatmya
et al., 2016), and this is a direct result of teachers not understanding the impact that culture and
race have on education. When disability status is layered in with cultures that are typically
overlooked in education, the students cannot achieve, and teachers need diversity training along
with training that takes place to instruct in inclusive settings.
Limitations and Recommendations for Future Research
It is impossible to ignore the small number of studies (11) included in this meta-analysis.
Variabilities that cause heterogeneity in the studies can and should be further studied, looking
specifically at what and why differences are there. There are several areas that could be looked at
for further research that could cause such variability in inclusive education research, including
this meta-analysis. As a specific example, in this meta-analysis, only two studies for elementaryaged students were used, which means results, especially for the age/grade level moderator,
should be interpreted with caution due to the incredibly small sample size and study number.
And, as with all research focused on effect sizes of specific interventions and influences, this
research could help identify research gaps and highlight areas that require further investigation
when it comes to inclusive education and its effect on Black and/or Latinx students. Limitations
or inconsistencies in existing literature may be revealed, and the hope would be that future
research directions and priorities could be guided by this current research and its findings.
An important area of note for future research is that of looking at the different types of
inclusive teaching practices and their effects on achievement. For this meta-analysis,

59
mainstreaming and co/team teaching were used together under the umbrella of inclusive teaching
practices due to not having enough studies to create a moderator in this area. Whether the
inclusive practice is that of full mainstreaming (no additional help in the classroom) or co/team
teaching (one special education teacher and one general education teacher), additional research
on whether one works better than another for minority students is an important data point to
consider when districts are making their decisions about teaching practices and least restrictive
environments for all students. Along with this, specific research is needed in the area of
age/grade-level differences for students of color. While this research showed that elementaryaged student samples with 40%+ Black and Latinx students were positive, more specific
information for grade levels such as lower elementary or middle school versus high school for
students of color could be incredibly beneficial as districts consider inclusive education options.
Another factor that could easily alter data for inclusive teaching practices that needs
additional research is the support provided in co-teach or co-lab inclusive classrooms by both
classroom instructional practices along with the adult in the room. Many studies show effective
results in co-teaching when a full-time general education and special education teacher are in
the room (Solis et al., 2012), which is what the studies included in this meta-analysis utilized,
but when looking at co-lab models that more typically have a paraprofessional in the classroom
instead of a special education teacher, research is scant. Additionally, when looking at inclusive
models that are labeled as co-teach, a positive fact is an additional teacher in the room, but not
all models of co-teach show the same positive results. The most popular model of co-teach in
which the general education teacher teaches while the special education teacher individually
assists students with disabilities does not typically produce statistically significant positive
results for students without disabilities, as they are not getting any additional help in this model

60
(Solis et al., 2012). However, there are alternative models of co-teach that produce better results
for students without disabilities and produce positive results for students with disabilities, those
being station teaching and parallel teaching (Hamilton-Jones & Moore, 2013). These types of
teaching strategies allow all students to be broken down into smaller groups, which allows more
access to a teacher, thus potentially improving achievement for all students (Murawski &
Lochner, 2011). So, while outcomes for students with and without disabilities may improve
depending upon the style of co-teaching, little research has been done on how different coteaching models specifically affect minority special education and general education students.
Depending upon the type of inclusive classroom students are in, along with the support
provided to the general education teacher, studies range in positive and negative impacts of
inclusion, and more research is needed on the specific effects on minority students.
Another recommendation for future, additional research would be the impact of
inclusive teaching on general education students. This study concluded that there was no effect
on general education students; therefore, additional research that investigates potential ways that
inclusive teaching affects general education students could strongly benefit the field, as the
continued focus on least restrictive environment for special education students will force more
and more districts into utilizing inclusive education.
Lastly, the samples of students with special needs utilized in all the studies found in this
meta-analysis rarely specified the specific type of disability the students qualified under.
Students who qualify for special education services range in a variety of different disabilities
and severities. What works for a mild/mod student who is deaf may be completely different than
what a mild/moderate student who qualifies under emotional disturbance needs in a classroom
setting to be successful academically. It is extremely important to note that generalizing the

61
results for any student with mild to moderate disabilities is a troublesome decision to make
when analyzing data, because so much of what a special education student needs to be
successful depends upon their disability. This meta-analysis used studies with all types of
special educational needs and qualifiers instead of breaking down the qualifiers separately,
which could not be done due to incomplete data and/or not enough data to create a moderator in
that area.
Conclusions
Teachers, administrators, district representatives, parents, and researchers can all benefit
from knowing the effect of inclusion on students, especially minority students, with and without
disabilities. For disabled students, inclusive classrooms show positive effects for academic
achievement, especially for elementary-aged students, although the effect sizes for general
education students were not statistically significant in this meta-analysis. Despite the statistically
nonsignificant effect of inclusion on general education, inclusion shows positive results for
special education students and, therefore, needs to be brought to the forefront of conversations
when discussing what is best for students. The additional costs of inclusive education (two
teachers per classroom instead of one) and the constraints put on master schedule building due to
cost in no way outweigh the importance of doing what is shown to positively impact the most
vulnerable student population, those with disabilities, especially when combined with the idea
that it positively affects Black and Latinx students as well. It should again be repeated that this
meta-analysis did not consider any social and/or behavioral data, which for many schools and
districts are just as important as academic achievement. While these effect sizes may be true for
the small number of studies included in this meta-analysis, district administrators and teachers
should continue to look at school-site data for their own students in order to judge whether

62
inclusive classrooms are beneficial in their specific districts. Outcomes will differ based on the
types of disabilities, grade levels, and other demographic makeup of school sites, and different
students need different interventions to be successful. Conducting a meta-analysis to find the
effect size of inclusive teaching practices on the academic achievement of Black and/or Latinx
students holds solid potential for advancing research in this area. By focusing on this specific
student population and the influence of inclusive teaching, several significant contributions to
further research could be made. First, the data provided in this meta-analysis could help to
establish a more robust evidence base and provide clearer understanding of the effectiveness of
inclusive practices for these specific minority groups who have disabilities. While there has been
significant research on the influence of inclusion on academic achievement for all students, this
specific research could enable practitioners to identify any disparities or differential effects that
may exist between Black and/or Latinx disabled and non-disabled peers who have classroom
interaction with disabled peers. Secondly, by investigating the effect sizes of inclusion
specifically for Black and/or Latinx students across multiple studies, it may be possible to
identify patterns that contribute to the positive or negative academic achievement outcomes for
this group of students. With this knowledge in mind, new designs of targeted interventions and
instructional strategies that promote positive academic achievement outcomes for these students
within inclusive settings could be integrated into inclusive settings with the hope of lessening the
opportunity gap for minority students.

63
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Appendix A: Studies Used in Meta Analysis
Study
no.
Study
authors
Publication School
level
No. of
general ed.
students
No. of
special ed.
students
%
Latinx
%
Black
No. of
effects
Average g
for gen. ed
students
Average g
for sped.
students
1 Harrison
(2011)
Dissertation Elem. 476 40 8% 39% 4 0.27 –0.12
2 Kluwin and
Moores
(1985)
Journal article Sec. 0 474 14% 31% 1 – 0.5
3 Kluwin (1993) Journal article Sec. 0 80 21% 34% 4 – 0.97
4 Murawski
(2006)
Journal article Sec. 83 48 38% 7% 20 –0.26 0.31
5 Osborne et al.
(1991)
Journal article Elem. 16 23 0% 62% 9 0.61 0.89
6 Barrocas (2011) Dissertation Sec. 80 80 100% 0% 4 –0.02 0.16
7 Belmarez
(1998)
Dissertation Sec. 41 55 52% 5% 6 –0.4 –0.28
8 Cawley et al.
(2002)
Journal article Sec. 98 0 43% 22% 4 –0.32 NA
9 Grimaldi (2009) Dissertation Sec. 45 0 34% 23% 4 0.37 –
10 Neugebauer
(2008)
Dissertation Sec. 4381 0 38% 10% 4 –0.24 –
11 Owoh (2013) Dissertation Sec. 0 52 0 100% 2 NA 0.47

79
Appendix B: Coding Guide
Considering the size and scope of the research study, coding was performed to ensure
that accurate information and data were pulled from each individual study, so the final effect
sizes presented in the study were correct. The coding guide was grouped into various
characteristic sections: meta-analysis, report, setting, participant information and sample
information, predictor/influence, outcome measures, type of research design, and experiments.
Studies were individually reviewed and screened multiple times before each study was broken
into parts and entered onto the coding guide by the author. Once the author finished the coding
process, a PhD student and the author’s chair checked the coding guide to ensure accuracy in all
information that was included within the coding guide.
Coding Guide Sections
• coder information
• date coded
• coder
• meta-analysis characteristics
• meta-analysis’ first author’s last name
• meta-analysis’ Google drive link
• report characteristics
• report ID number
• article Google drive link
• author’s last name
• year
• title

80
• APA reference
• publication type
• data sources
• dataset name
• data collection year
• year(s) data was collected
• overlapping data sets
• setting characteristics
• study number
• location of study
• region of study
• school level of students
• elementary or secondary school level
• classroom type of experimental group
• school type
• Participant and sample characteristics
• type of sample
• subgroup specification
• subgroup overlap
• subgroup overlap explanation
• sample size (at start)
• sample characteristics
• % White

81
• % Black
• % Hispanic
• % Asian or Pacific Islander
• % Native American or American Indian
• % other
• grade level
• % female
• % low income/economically disadvantaged
• % special education
• % English learners
• disability type for special education students
• student sample type (disabled or non-disabled)
• experimental group definition
• control group definition
• predictor/Influence
• report’s name for influence
• influence definition
• how the influence is measured
• reliability
• alpha coefficient
• how influence is manipulated by researcher
• type of experimental classroom used
• type of co-teach model used

82
• % of special education students in classroom
• outcome measures
• outcome type
• outcome name
• outcome description
• domain of outcome
• unit of analysis
• timing of influence and outcome measure
• specify timing
• outcome domain (STEM or humanities)
• Type of research design
• size (for relationship/effect)
• direction of relationship between influence and outcome
• evidence of direction
• type of research design
• treatment and control group presence
• evidence of random assignment to treatment and control groups
• level of assignment
• evidence of matching of treatment units to comparison units
• matching characteristics
• reported prior influence or pre-test statistics
• regression
• multi level/hierarchical modeling

83
• experiments (including quasi-experiments and randomized control trials)
• number of students in treatment group
• number of students in control group
• mean of treatment group
• mean of control group
• standard deviation of treatment group
• standard deviation of control group
• effect size
• variance
• Screen shot of online calculator that was used to computer effect size and
variance.
• evidence that a d-index was calculated
• effect size from original meta-analysis

Abstract (if available)

Abstract Inclusive teaching practices, sometimes known as mainstreaming or co/team teaching, are an intervention that schools and districts use wherein special education students and general education students are educated within the same general education classroom using general education standards and curriculum for education. A research synthesis was conducted on the effects of inclusive teaching practices (both mainstreaming and co/team teaching combined) on academic achievement for K–12 students. Specifically for this synthesis, only studies where the sample population was a minimum of at least 40% Black and/or Latinx students were used. A meta-analysis of 33 samples from 11 inclusive teaching studies with a total of 62 effects revealed a positive and statistically significant average effect on achievement (g = .2740). Variations in effects emerged depending on the student grade level, percentages of Black and Latinx students in the sample, and disability status of students. Overall, results highlighted the importance of considering the grade level of students when deciding on inclusive teaching practices along with the need for more research centering on types of co/team teach models and disability types when making curricular decisions. Additional implications for theory, research, policy, and practice are discussed.

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Core Title The effects of inclusive education on academic achievement for special education and general education students of color: a meta-analysis

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