A REVIEW STUDY OF RESEARCH ARTICLES ON THE BARRIERS TO INCLUSIVE EDUCATION IN PRIMARY SCHOOLS

This article presents a review of research studies related to the theme of barriers to inclusive education in primary schools. The basic data set for our study consisted of 27 expert articles selected from the Web of Science and Scopus databases according to clearly defined criteria. The result of the analysis provided findings that appear across all the texts. The research questions of this review study are what the barriers to inclusion in primary schools are, what we know about them, and whether there are ways to reduce them. We focused in more detail on the themes of discrepancies between legislation and practice, teaching barriers in the classroom, transdisciplinarity and inter-professionalism, and methodological specifics. In the analysis and discussion, we delineate the essential points of the individual articles by searching for similarities and differences among the texts.


INTRODUCTION
For more than four decades now, the theme of inclusivity has been becoming increasingly relevant in global discourses on education.The principle of inclusive education (IE) is firmly grounded in discourses of human rights and social justice.In 1994, 92 countries of the world signed the Salamanca Statement, introducing the novel concept of IE for children and adults with special educational needs (SEN).The definition of inclusion in the Statement is quite broad and goes beyond the concept of disability to include 'Education for All' (EFA), a target specified by many regional and international organizations in various initiatives since Salamanca.The basic principle of inclusion is that all pupils should learn together whenever possible and that mainstream schools must respond to the diversity of individual pupil needs.To this end, schools must receive adequate support and services.Most international organizations involved in the field of education have adopted this comprehensive approach, including groups sponsored by the United Nations (UNESCO, UNICEF), the Council of Europe and the European Union (Hardy and Woodcock, 2015).

Review study
Participants at the World Education Forum in Dakar further recognized that 'the heart of EFA activity lies at the county level' (UNESCO, 2000: 10).At present, a definitive shared framework for the concept of inclusion has not been agreed upon (Armstrong and Cairnduff, 2012;Tso and Strnadová, 2017), although a number of concepts have emerged.One indisputable finding is that the feeling of belonging to a school further correlates to greater life satisfaction and better academic results (OECD, 2017(OECD, , 2018)).The decisive factor towards securing real inclusion for all are teachers (Choi, 2018;Riley, 2017).Many educators have reported that they do not regard themselves as sufficiently prepared for their role as inclusion actors (Cologon, 2013;Soto-Chodiman et al., 2012), a feeling which is also reflected in the emotions they experience as inclusion is realized in pedagogical practice.As the inclusion of pupils with disabilities has always been a prominent issue in general discourses on inclusivity (Clough, 1998;Davies, Garner and Lee, 1998), naturally, questions have arisen regarding the appropriate formulation and institution of educational policies along these lines (Barton, 1986); Davies, Garner and Lee, 1998).Strategies were once based largely on market competitive comparisons of the educational results of individual schools, yet this is an approach that has been found to make real inclusion impossible.Inversely, a number of studies have focused primarily on factors related to social inclusion (Mowat, 2019), featuring many key elements, such as a general sense of belonging (Riley, 2017), relationships within the school (Bossaert et al., 2013), as well as other affective factors that function as motivational and protective elements (Prince and Hadwin, 2013).IE has been described as 'the process of educating children with disabilities in the regular education classrooms of their neighbourhood schools -the schools they would attend if they did not have a disability -and providing them with the necessary services and support' (Rafferty, Boettcher and Griffin, 2001).Inclusivity as 'Education for All' concerns not only the mere physical placement of pupils with SEN in the local school but also improving the conditions of social life in the school community and enriching the learning environment.Inclusion also concerns the specific way of teaching, which includes supporting all actors involved, thereby securing the benefits of such education (Haug, 2003).
As the results of our study show, inclusion is a global phenomenon, with studies showing tension in various environments worldwide between educational policy and the practice that individual inclusion actors seek to implement (Anderson, Klassen and Georgiou, 2007;Daly et al., 2016).Despite good intentions, the insensitive or ineffective implementation of educational policy in relation to inclusion can potentially lead to anxiety or even friction among all actors involved (Raffo and Gunter, 2008).Our review study aims to describe particular barriers inclusion actors have encountered and dealt with in different cultural contexts.Then, using this information, we seek to determine particular common denominators within the basic research discourse.Meeting both of these goals can help set more effective educational policies, improve teacher training, and point to directions for future research into IE.Inclusive, internally differentiated education of pupils during compulsory schooling, has been shown as a highly desirable model (Idol, 2006), which not only enhances the cognitive development of all pupils but also has a positive effect on pupil socialization (Hunt and Goetz, 1997;Mowat, 2019).The authors of the present paper wish to use this text to support an inclusive philosophy that is both fairer and more beneficial for all pupils and students.

RESEARCH METHODOLOGY
The aim of our review study is to describe the research discourse in the field of barriers to IE within primary school.We will attempt to analyze the most frequently discussed topics in both content and methodology.Findings have shown that inclusion is commonly portrayed as problematic in some media and is perceived as such in the wider society (Brown 2020;Gilmour, 2018;Whitley and Hollweck, 2020and to highlight the particular case of inclusive education policy reform in the province of Nova Scotia.As with most other provinces and territories, inclusive education policy in Nova Scotia has broadened to include a lens of equity, with a focus on not only students with special education needs, but all students -particularly those most often marginalized by and within Canadian school systems.The article reflects on the first phase of the developmental evaluation process which took place prior to full implementation of the policy.Four interconnected key themes emerge: 1).Also, authors more accommodating to the concept of IE have indicated the many problems that exist in the media space (Jack and Manoeli, 2020;Murphy, 2015).As our goal is to review how the relevant professional literature describes the particular barriers that appear in the field of IE, as well as how IE as a whole is described in terms of barriers, we will leave aside discussions of media portrayals; although this is a very valuable research area, e.g. in terms of providing the public with accurate information regarding IE.The research questions of this review study are what the barriers to inclusion in primary schools are, what we know about them, and whether there are ways to reduce them.To shed light on our research, we draw on the paradigm of action research (Zuber-Skerritt, 2001;Ketterer, Price and Politser, 1980).This emphasises the need to understand the status quo and discover the mechanisms that can lead to the desired positive change.Our research is also linked to change -we are looking for ways in which barriers to inclusion can be removed.For our review study, we chose the search terms 'inclusion', 'primary school' and 'barriers'.The aim was to examine texts that deal either generally with the issue of inclusion in the field of basic education (especially at the first stage, i.e.ISCED Level 1), or more specifically with barriers that may be associated with its implementation.As our research target relates to the school environment, it was necessary to exclude from the search results texts directed toward other domains, e.g.STEM fields, the legal and health professions, other fields in the humanities, etc.A few texts, including the search terms that were completely unrelated to the research area, were also excluded from the analysis.The search filter was set to the years 2017-2020.Since our analysis aimed to depict the current situation, we did not explore older texts.The texts were sourced from the Web of Science (WoS) and Scopus databases, which we chose as they feature the highest quality texts in terms of professional and scientific excellence.If a text was indexed in both databases, we chose the version listed in WoS.A total of 21 texts were retrieved from the WoS database, along with another 6 from Scopus, thus, we worked with a total of 27 documents in the analysis.Exclusively research articles were included.The review study is limited to the years 2017-2020 for two reasons: the first is that barriers to inclusion are well described in older literature or textbooks (Darrow, 2009;Lloyd, 20081997;Powell, 2015) and the aim of our study was not to extend the period of the studies reviewed and to petrify these findings, but to offer insights into current research approaches, methods, findings, and perspectives.The second is the qualitative focus of the study, which allows for detailed work only on a limited number of studies.Thus, the reduction to this time period fulfills both an updating and selective role so that the chosen approach is methodologically transparent.We undertook both a qualitative and quantitative evaluation of the texts.The qualitative part consisted of the analysis of noteworthy findings and other information that facilitates a clearer understanding of barriers to the implementation of inclusion in primary education.All three authors of the present review study read all of the texts, following which the qualitative analysis was conducted.After the methodologically more subjective qualitative evaluation, a quantitative analysis was conducted.For each text, the sample size and its structure, methods, research tools, data processing methods, and location were determined.
We also originally intended to analyze the research questions of the articles but this was not successful since many articles (even empirical studies) did not work with explicit research questions at all.Similarly, not all the texts share a clearly defined research paradigm on which to rely.Thus, while for most of the articles it is possible to assume the prevailing constructivist presuppositions, in no text was it possible to identify them methodologically.For this reason, in the resulting table, findings regarding evaluations of the research questions are not featured at all.In general, qualitative concepts prevailed (22 of the studies).
A large part of the texts described research that employed a methodology that produced results that were not very acute or unambiguous, using methods such as thematic analysis, content analysis and/or semi-structured interviews; Interpretative Phenomenological Analysis (IPA), ethnographic methods, etc. were also represented.Our findings show that qualitative methods have usually been regarded as more appropriate in examining themes related to inclusion, as the concept is typically seen in terms of relatively broad and complicated phenomena.The fact that we do not have quality large-scale quantitative studies (6 in total, out of which 4 were purely quantitative and 2 mixed design) should also be emphasized.A few single and multiple case studies (3) were also represented.

RESULTS
The 27 studies included in our research were carefully analyzed by the three authors, who then agreed on the key messages of the individual studies.In addition to summaries of the findings of each study, the attached table in the appendix also shows the geolocation of the individual surveys (11 studies from Europe, 1 from America/ Caribbean, 4 from Asia, 6 from Australia, 5 from Africa) along with research methods (most often various forms of interviews -21, questionnaires or tests -10, and observations -5).The sizes of the research samples were quite diverse, ranging from a set of 2,649 pupils to single cases and case studies.It is not possible to determine one dominant target group of research, although most often the research included teachers (16), pupils (5), and parents (5), as well as assistants, school principals, and administrators.Research results have been mapped, documenting the experiences of more than a thousand teachers, three thousand pupils, and more than four hundred other inclusion actors.It can thus be argued that the presented results capture a relatively extensive, multiculturally diverse set of experiences at the time of the study, which has allowed the researchers to observe in a broader way, certain general trends regarding barriers to the process of IE in primary schools.

Data analysis
Within our research framework, we processed the 27 texts using a combination of two methods: content analysis followed by framework analysis, which we used to examine the most general characteristics of the analyzed texts.In the appendix of this article is a table with selected data that we have chosen as relevant.We identified certain common structures that were found in a substantial portion of the analyzed articles.Four areas were identified as the most common and important.They are the result of the thematic analysis carried out.This is the core of the analytical review, which we focus on in a broader and deeper analysis below.

Discrepancies between legislation and practice
The OECD report (1999) argues that although there is a consensus in the international context on what comprises IE, the main barriers to implementing IE in practice show a combination of a lack of political will and an endless resistance to change.The broad definition of IE enshrined in the Salamanca Declaration (UNESCO, 1994) and the Framework for Action (UNESCO, 2000) is reflected in the national legislation of many countries, especially the signatories of this declaration, e.g.Trinidad and Tobago (Parey, 2022), Australia (Hodges et al., 2020), South Africa (Materechera, 2020), and Great Britain (Alderton and Gifford, 2018).In most of the texts analyzed, a noticeable emphasis has been placed on specific national policy contexts (Alborno, 2017;Daly et al., 2020;Parey, 2022).The breadth of the internationally supported definition of IE must be reflected at the national level, albeit in various forms.In the 21st century, most countries cannot afford to claim that education should be of a purely exclusive nature or that people with a certain otherness should be segregated, as stated in Convention on the Rights of the Child -Article 2 (UNICEF, 1989) and Convention on the Rights of Persons with Disabilities -Article 24 (UN, 2006).This means that the idea of humanity as a social invariant represents a relatively broadly accentuated concept within the value framework of individual countries (Glass, 2001).Still, a strong gap remains between the declared value framework of IE enshrined in national education policies and public attitudes (Alborno, 2017).We can see pressure supporting IE as a fundamental human right, but we can also feel considerable resentment from parents and the general public.They feel that any otherness hampers other pupils and delays their development, negatively affecting their educational outcomes (Ebuenyi et al., 2020;Keon, 2020).In the Irish context, these attitudes reflecting public antipathy have been termed 'soft barriers' (Cradden, 2021;Keon, 2020).Teachers are thus placed in a situation in which they must liaise with parents, yet still emphasize a partnership-oriented and open approach that is often in sharp contrast to the value framework of parents (Hodges et al., 2020;Keon, 2020).This tension, often framed in terms of a 'mismanagement of public debate', is indicated as a strong negative aspect regarding inclusion in most of the studied texts (e.g.Ireland: Keon, 2020; United Arab Emirates: Alborno, 2017; Australia: Hodges et al., 2020;South Africa: Materechera, 2020).
Another manifestation of the conflict between legislation and practice is illustrated by the example of Trinidad and Tobago: 'The participants shared that the Equal Opportunities Act was the only piece of national legislation which secures the rights of children with disabilities with regards to inclusion in schools in Trinidad.They mentioned that, due to the absence of monitoring mechanisms, the implementation of this legislation was not strong.'(Parey, 2022: 569).In practice, this means that different countries across continents (Trinidad and Tobago: Parey, ( 2022 2018) have instituted an inclusive school legislation that sets a strong systemic and value framework only in some respects.IE is seen as intended and even desirable, and putting school legislation into practice is considered to be primarily the job of the school.Nevertheless, despite well-intentioned efforts, no mechanisms exist that would support the practical implementation and evaluation of an inclusive form of education in schools (Tannenbergerová, 2018).Additionally, problems may also stem from a disparity between a country's cultural roots and its official IE policy (Qu, 2019).In Confucianism, which shapes the Chinese idea of a highly homogenized society, great emphasis is placed on harmony and order (Li, 2006).Whatever violates this order is perceived as negative, and the goal of education is to eliminate this contradiction (Qu, 2019).In such a situation, inclusion, which in itself entails the existence of otherness, is a concept very difficult to integrate culturally with the desideratum of stability and consistency.When IE is viewed through a special pedagogical or human rights prism, it becomes necessary to clearly define the widest range of possible disadvantages and needs that a teacher may encounter in the classroom (Ebuenyi et al., 2020).If not, misunderstandings will arise, and in the worst case, segregation may occur in situations where it otherwise would not have occurred at all.

Educational barriers in the classroom
In addition to the aforementioned discrepancy between social and legislative norms, throughout the analyzed texts, specific barriers are described that stand in the way of successful inclusion.The emphasis on the feeling of the lack of help is critical.Inclusion is perceived as something that needs to be accomplished, but at the same time it always has the character of something extra, simply another requirement placed on the already overburdened school ecosystem.Results concerning IE have been closely related to the quality of teaching and learning (Cara, 2013).Educators and teaching assistants feel unprepared for an inclusive classroom environment, and also lack continuing professional development (CPD) regarding work with a heterogeneous classroom (Anglim et al., 2018;Mukhopadhyay et al., 2019;Smith and Broomhead, 2019).A total of five texts touched upon the theme of working with children and pupils with autism spectrum disorder (ASD) (Anglim et al., 2018;Hodges et al., 2020;Kerins et al., 2018;Tso and Strnadová, 2017).In other articles, we noted mentions 120 ERIES Journal volume 15 issue 2 Electronic ISSN 1803-1617 of unpreparedness for working with ASD or, alternatively, with a group of pupils with social, emotional, and behavioural needs (SEBN, a specific group which also includes pupils with Emotional and Behavioural Disorders) (Alborno, 2017;Kerins et al., 2018;Mowat, 2019;Mukhopadhyay et al., 2019;Suc et al., 2017).Another interesting finding is the relationship between didactic methods and inclusion in schools, with a close connection shown between didactic methods and the results of IE (Martos-García and Monforte, 2019; S. Sánchez et al., 2019).In general, frontal methods that emphasize a Foucault division of power work less effectively with inclusion; in contrast, strongly activating and socializing projects (associated with teamwork along with shared practical and enjoyable experiences) have a relatively large potential to support IE in a number of ways (Alderton and Gifford, 2018).Keeping all of this in mind, exactly how should future and current teachers be prepared to face the challenge of working with heterogeneous school participants?In addition to the weak support in terms of both undergraduate preparation and further education of pedagogical staff, in the analyzed texts, we noted other factors of a material nature hindering or preventing the adoption of an inclusive curriculum altogether.In some countries, education actors must work with outdated or dilapidated classroom equipment, or they must deal with the unavailability of supporting educational materials and other inadequate teaching resources (Mowat, 2019;Mukhopadhyay et al., 2019).One respondent of research conducted in South Africa's mainstream schools communicates these concerns: 'Inclusive education can work if classes are not too big.So, more educators need to be employed, because if the classes are as big they are now, where some teachers have 52 pupils, it's terrible; there is not even space in the class to move around.That's why I say the teachers are already negative about this inclusive education […]'.(Mukhopadhyay et al., 2019: 780).The common denominator of all these barriers is the lack of financial resources.

Transdisciplinarity as a challenge
Inclusion has always been characterized by a transdisciplinary approach, which is central to whether the inclusion process works or fails.Alborno (2017) indicates the large number of actors, i.e. inter-professionalism, who must be involved in the process of IE.It is necessary to ensure that all the participating actors are able to confer with each other and cooperate, that they respect each other and are able to pursue common goals.However, in the current overall climate, it seems such an ideal situation rarely occurs.Like the obstacles regarding classroom barriers, it seems that much more could be done to establish the transdisciplinary approach as a goal, both in theory and practice (Kerins et al., 2018).This objective has proven difficult to fulfill with regard to the diverse professional identities and the sometimes divergent views of individual actors involved in educational processes (Kerins et al. 2018).This situation often leads to less common pedagogical concepts and procedures (Quibell et al., 2017), or experimental research designs (Ndhlovu and Varea, 2018) based solely on one discipline to the exclusion of others.
The theme of transdisciplinarity in IE was analyzed by Suc et al. (2017).They found that teachers perceive cooperation with other professions (health professionals, psychologists, counsellors, social workers) very favourably and as an activity from which they benefit in practice.On the contrary, therapists perceived interdisciplinary cooperation within a much smaller scope, with their contact with educators primarily taking the form of information transfer.Therefore, certain basic issues, even the definitions of work expectations and responsibilities, must be dealt with in terms of interprofessional communication for effective inclusion to be implemented.One finding which emerges from the research is the need to rethink the very meaning of transdisciplinarity in the context of IE, along with the implications of such an approach (Suc et al., 2017).Transdisciplinarity entails not only information transmission but also a process of adapting educational methods and approaches, examining socialization interactions in relation to school architecture, as well as many other sub-dimensions in which it will become necessary to search for genuine interdisciplinary and inter-professional cooperation (Overton et al., 2017;Sánchez, Rodríguez and Sandoval, 2019).Given the general results identified in current research, however, a degree of scepticism may be expressed as to whether teachers, teaching assistants, counsellors and other professionals are really prepared for such an approach (Alborno, 2017;Ebuenyi et al., 2020;Mukhopadhyay et al., 2019).The fact that IE cannot be tackled at the level of a single worker or specialist but can only be achieved consortially is also evidenced in studies on people with disabilities (Hankebo, 2018; Martos-García and Monforte, 2019), specifically people with autism, whose inclusion is possible only through a cooperative synergy among several professions and professionals (Anglim et al., 2018;Imasaka et al., 2020;Kerins et al., 2018;Tso and Strnadová, 2017).Hodges et al. (2020) illustrate this theme in the relationship between social integration and school culture, emphasizing that it is not possible to achieve real IE without social pedagogical intervention.

Qualitative research designs with no ambitions to formulate more general theoretical hypotheses predominate investigations into IE
This research reality also reflects the situation described above in the reported results.Steps toward inclusive measures are usually of a partial nature, embracing a limited approach that does not go far enough towards resolving major issues such as teacher training, specialist interdisciplinary cooperation within the school environment, the provision of resources for assistants and aids, as well as other challenges which must be met for IE to be successfully implemented.Qualitative research designs, showing no inclination toward formulating more general theoretical hypotheses, predominated our review study.Limited perspectives on broad problems, as well as examinations of isolated phenomena in specific situations, are explored, although sometimes in original or otherwise interesting ways.Generally, few precise measuring instruments are used to produce results that could later be related to specific government policy recommendations (Qu, 2019).If we ask why inclusion is failing, or at least is not

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1803-1617 proceeding as robustly as it could, one of the reasons may be a lack of quantitative research that could influence specific policy measures, e.g. by creating information feedback loops between policy makers and on-the-ground inclusion actors.This practical failure at the school and classroom level is especially disheartening in situations where strong legislative initiatives have already been implemented.Innovative and experimental qualitative methods produce extremely valuable knowledge and insights that cannot be obtained in any other way, often by giving a voice to the voiceless, in our case pupils and their teachers.We do not intend to portray a negative characterization of qualitative research tools, but only to draw attention to the fact that by their very nature they generally lead to a description of only one particular situation (Alborno, 2017) or the experiences of a unique group of people (Miles et al., 2018).We only seek to point out that often qualitative methods are not grounded in, nor do they lead to, broader frameworks of thought.It is imperative that isolated qualitative studies, which in our review are shown as prevailing in inclusivity research, be supplemented to a much greater degree by more quantitative research to obtain a comprehensive view of the special issues related to IE, including barriers to full implementation.
Although, as indicated, qualitative approaches predominate quite convincingly in our review, four studies were of a purely quantitative nature.The first was a Spanish paper by S. Sánchéz et al. ( 2019) in which over 2,500 learners completed a questionnaire, culminating in information about the possible construction of a valid and reliable tool that would facilitate work with easily measurable quantifiers.The second article focused on working with a questionnaire for principals and special pedagogical assistants (Kerins et al., 2018), while the third uses Spahiro-Wilk statistics to compare results from two groups (outdoor and indoor learners) of respondents (Quibell et al., 2017).In the fourth purely quantitative research work, the authors chose a study group and a control group for which multiple statistical techniques were used (Vallaba Doss et al., 2020).Only in two selected studies did the authors use a mixed design of quantitative and qualitative methodology (Materechera, 2020;Parey, 2022); in both cases, the authors combined in-depth interview methods and questionnaires.
The review findings emphasize in particular the absence of a strong theoretical framework as the basis for the structured interviews or quantitative methods.As stated previously, although these studies often present interesting results, no unifying concept or theory is presented to form discussions or conclusions that may be useful in broader contexts.It has been established that inclusion in the school environment has been thoroughly researched and reflected upon using these methods.Researchers have put forth efforts to improve the current situation in the local or even regional context, e.g.(Ebuenyi et al., 2020;Mukhopadhyay et al., 2019), but a research knowledge gap remains in terms of the formation and application of broader models and theories that might be applied more universally, i.e. a set of basic principles from which to start.The situation is one in which the relatively large amount of data obtained through in-depth interviews (generally processed through IPA, but also otherwise), as well as semi-structured interviews, is too fragmented to form a deeper framework.

DISCUSSION
IE (Lindner and Schwab, 2020;Nilholm, 2021), as well as its challenges and barriers; Schuelka et al., 2020), represent a necessary research and application topic with a solid multicultural dimension (Hayes and Bulat, 2017;Ramberg and Watkins, 2020).The analysed studies show that this topic needs to involve many helping professions (Baird and Mollen, 2018;Walsh et al., 2020), whose approaches can help with a multidisciplinary and transdisciplinary approach.The topic of inclusion is not just a school issue but extends to the entire social environment of educators, pupils and students.
An educationally adequate method that removes barriers will better integrate pupils or students with specific learning needs and transform the whole social discourse (Liasidou and Symeou, 2018).Therefore, it is an essential topic for all, as it leads to the systematic inclusion of differences in education (Mestenhauser and Ellingboe, 2005;Woodruff, 2020), which we consider an essential pedagogical issue (Eisenberg et al., 2021).
In our study, we have left aside topics that are purely focused on special educational issues because we believe that IE discipline as a whole is capable of taking a good stance on such problems and strives for this kind of inclusion through the education of future and current teachers (Felder, 2021;Florian, 2019;Paseka and Schwab, 2020).Similarly, we have left aside topics such as lack of material or economic security or lack of political support because what we want is to describe the changes that education can make (Nilholm, 2021).An interesting aspect related to internationally recognized legislation is that the theme of IE has become topical across continents, which also reflects the transcultural nature of IE.
We can currently observe the world's interconnectedness regarding this issue in the adoption of transnational documents on education (e.g.Salamanca Statement), although it is understandable that discourses of inclusivity continue to be

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ERIES Journal volume 15 issue 2 Electronic ISSN 1803-1617 reflected in diverse ways in local policies within particular national contexts.As we have shown in the example of China (Qu, 2019), the promotion of IE may be associated with a certain value-environment or historical experience (Materechera, 2020).Despite national and regional idiosyncrasies, however, the basic scenery in which inclusion moves in the school environment is similar.In the majority of the analysed texts, in terms of the understanding of IE 1 the authors refer to the Salamanca Statement (UNESCO, 1994).Nevertheless, the research shows a discrepancy between the declared broad understanding of the concept of IE and practice in specific schools, which for many reasons often do not receive adequate support (Anglim et al., 2018;Kerins et al., 2018;Mukhopadhyay et al., 2019).In such a situation, IE is reduced to the mere physical integration of pupils with special educational needs, i.e. the presence of these learners does not significantly affect the current course of the class and the educational process.'If inclusion, for all its complexity, is such an important principle, why is it not a readily identifiable, stand-alone entity in policy?And why is inclusion so often only mentioned in passing in many policies?'(Hardy and Woodcock, 2015: 145).When international and, therefore, national legislation has already defined the conception and form of IE, then is it still now appropriate to ask how we will reflect and support this legislation in practice?The inadequate training of pedagogical staff and consequential lack of experience of work with the specific needs of pupils has been identified in our research as a basic barrier standing in the way of IE (Anglim et al., 2018;Hodges et al., 2020;Tso and Strnadová, 2017).The literature identifies two possible, and in some ways antithetical, pedagogical approaches (Haug, 2017).Impairment-oriented teaching strategies focus on learner pathologies along with the particular personal difficulties associated with specific learning problems related to each condition.To support pupils and students and their particular needs, the school needs special educators who understand specific impairments as well as know how to compensate for them (Kreitz-Sandberg, 2015).The second approach, referred to as 'good all-round teaching' (Mitchell and Sutherland, 2014), is based on the principle that common teaching strategies, suitable for the majority of pupils, are also suitable for pupils with special educational needs.Each individual is different, thus as is the case with the general learner population, some pupils with SEN undoubtedly need more time, more repetitions, fewer tasks, and a slower progression, as well as, in some cases, adjusted performance expectations.Still, specific teaching strategies in this approach may be the same for all pupils regardless of their needs.In this case, the need for regular teachers in inclusive schools who are highly qualified in SEN, becomes even more imperative (Florian, 2014).In the context of transdisciplinarity, Kearney and Kane (2006) distinguish two interpretations of inclusion: (a) inclusion based on a special education framework and special teacher expertise, and (b) inclusion as meeting the needs of all learners in similar ways irrespective of what those needs are.The divergence between these two approaches is clearly visible in the results of our review study.Responding to the widely agreed upon identification of transdisciplinarity as desirable and necessary, although difficult to attain, Haug (2017) describes an ideal state which, unfortunately, is not realized in practice.Without a transdisciplinary approach (Rausch, Bold and Strain, 2021), it is impossible to institute IE and to successfully promote the collaboration of individual social (Bellamy et al., 2013) and special educators who, working together, might promote inclusivity even more effectively (Weiss, Cook and Eren, 2020).In this respect, it can be said that it is the capacity for the various supporting professions to communicate with each other that builds a transdisciplinary approach (i.e.interprofessionalism), which in turn is the basic prerequisite for successful IE (Rausch, Bold and Strain, 2020).The 'good all-round teaching' approach is supported by the results of one of the studies we analyzed (Anglim et al., 2018).This research provides clear confirmation that teachers with higher self-efficacy tend to adapt more readily to working with the individual needs of learners, with educator creativity also playing an important role.Schoolteachers need to trust that they are adept at teaching all children, an attitude also supported by being open to new trends in inclusive education (Florian, 2014) as well as continually seeking effective new approaches for their work.Last but not least, building relationships in the class collective among all actors involved is of fundamental importance.The support-group leaders in research conducted in Scotland (Mowat, 2019), as well as physical education teachers in an Australian study (Overton et al., 2017), identified good relations between teachers and children, as well as among pupils themselves, as an essential component of the educational process.The selected research studies are characterized by diverse methodological approaches.In most cases, the authors tended towards qualitative design, although mixed or purely quantitative designs are also represented.The predominant research methods are interviews (semi-structured, unstructured), in-depth interviews, focus groups, and observations; some authors also used questionnaires and document analysis.The most common data processing method was shown to be interpretive phenomenological analysis, with open coding and narrative methodologies less often represented.The analyzed research studies do not provide empirically obtained data that could form a concrete comprehensive theory of IE.Research in the field of IE is too fragmented and lacks a theoretical basis to frame the topic.The studies we analyze clearly show that inclusion is almost always a phenomenon that is perceived as beneficial and important for the future of education (Alborno, 2017), for the preservation and development of social justice (Hawkins, 2014;Wymer and Rundle-Thiele, 2017), as well as the effective overall functioning of school systems (Christensen et al., 2007;Ghosh and Galczynski, 2014).Regardless of whether inclusion concerns people with disabilities or other social groups, it is clear that a plan to overcome the four basic types of barriers 1 IE as "Education for All" involves not only the placement of pupils with special educational needs in the local school but also the conditions of social life in the school community as well as teaching and learning in the school.Inclusion then concerns how teaching is organized, the activities of teachers and students (support, involvement and participation) and the benefits of such teaching and learning (Haug, 2003).

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1803-1617 mentioned above will require new tools for change as well as functional inclusive measures.Based on our review, we can recommend that the following steps be implemented: • It is essential to provide effective and systematic training as well as material assistance for teachers as well as teaching assistants.• It is necessary to devote attention not only to proclamatory documents but also to the support of specific school practices in terms of material, methodological and organizational functions.• Despite the institution of various systemic measures, the quality of the teacher and the need for care for the individual pupil in a specific environment must still take top priority, which requires the preventive support of quality prosocial relationships among all actors in the educational process.

CONCLUSION
In our review study, we have attempted to collect and compare findings on barriers to IE as well as other related issues.Equal and quality education should thus be guaranteed by the school system, which should facilitate the maximization of the full potential of all (Gordon, 2013).In all the analyzed texts, we have found the general concurrence that inclusion is both supported in legislation (UNESCO, 1994;Alborno, 2017), and that teachers perceive it as something they should engage in.At the same time, however, the texts we reviewed articulate the view that schools and teachers do not have the support, education, competencies as well as other tools to effectively institute IE.Another widely discussed issue is the frequently reported scepticism of parents of the majority of society (Alborno, 2017) regarding the phenomenon of inclusion.It remains a major challenge to education systems as well as to individual schools to positively affect this social and cultural climate, as shifts in attitude over time will have a great influence on the successes and possibilities that real inclusion could bring.Four key types of barriers impeding successful IE can be identified as: • Systemic -systemic barriers (Tannenbergerová et al., 2018) can be seen in terms of the inconsistencies between legislation and practice.The publicly declared values associated with international documents such as the Salamanca Statement form isolated elements with which other legally understood measures are not yet sufficiently linked.• Personnel -barriers in the area of personnel can be seen mainly in the unpreparedness of teachers and other actors in education for a truly inclusive approach in IE.This barrier is relatively easy to remove through quality education with sufficient funding.• Transdisciplinary -IE is simply not institutable at the level of a single profession but requires the broad cooperation of a large number of various types of specialists.Ensuring both their presence in schools and mutual cooperation can be perceived as a primary task.• Methodological -as our review shows, while the theme of barriers to inclusion has been well researched in various local contexts, a lack of research grounded in broader concepts and theories persists.More generalizable results would allow the development of clear strategical frameworks, which in turn could foster the advancement of more effective measures to alleviate personnel and systemic barriers to school inclusion in the contemporary context (Booth, Ainscow and Vaughan, 2011;Symeonidou, 2017).These four principles can be seen as the key concepts that emerge from this review study.By limiting them to the primary school setting, their clear relevance to that setting can be perceived.At the same time, we can assume that other school levels responding to IE may face similar issues that would be specific to the particular level of education (Buysse, Wesley and Keyes, 1998;Dymond et al., 2013;O'Brien, 2020).

ACKNOWLEDGEMENT
This article was researched and written with funding support from the project Roads to the Inclusive School of the 21st Century: An Ethnographic Approach -GA19-13038S, supported by the Grant Agency of the Czech Republic.
); Slovenia: Suc et al. (2017); United Arab Emirates: Alborno (2017); United Kingdom: Alderton and Gifford (2018); Ireland: Kerins et al. (2018); Australia: Hodges et al. (2020); Tanzania: Miles et al. ( • It is necessary to support not only teachers but also all other actors in education towards specific pro-inclusive measures.• Regular dialogue must take place among all professions involved in the process of inclusion in the school to ensure maximum cooperation.Individual actors should not feel that they are in competition with or against each other but should strive to create an environment that generates cooperation opportunities.• It is essential to conduct long-term and systematic research in order to understand both barriers to IE as well as positive examples of inclusion in practice.The fact that there is no empirically-based unified theory of barriers to inclusion in the school environment significantly complicates the coordination and effectiveness of individual measures and interventions.• It is necessary to institutionalize research in the field of inclusion in order not only to monitor the overall quality of education policies but also to evaluate the effectiveness and efficacy of individual approaches and support programs as well as to communicate that information at the international, national and institutional level.