Didactic dimensions of teaching content for and with students with intellectual disabilities (ID): a scoping review

Decisions schools make about teaching content fundamentally shape students’ educational experience and their later life. These decisions often take a particular shape for students with intellectual disabilities. Although such decisions for this group are a prime concern in the governing and practice of education, they have gained little attention in research. Research that does investigate teaching content for students with intellectual disabilities often makes a distinction between Life Functional skills (LFS) and Academic Content (AC) and treats these as being quite separate. The study at hand explores the nuances of and relationship between the two through a scoping review, and contributes knowledge on didactical aspects and the how and why of teaching content as depicted in research. Results indicate that research on teaching content entails a complex process of valuing the content in which AC and LFS often overlap. Results also illustrate that students and teachers are absent from the research on teaching content and not included as active participants; researchers’ meth-ods often take precedence over teachers’ and students’ valuing of teaching content or methods.

taught in more detail.We contribute to the body of research on teaching content for students with ID further and provide a more nuanced account of its selection and justifications (Ayres et al. 2011;Moljord 2018;Olsson 2022;Shurr and Bouck 2013).We do this through a scoping review of how teaching content is privileged, characterised, and justified in existing research.What we mean by justification is the rationale behind the choice of teaching content and its significance for the students' future.Hence, we have reviewed earlier research to explore what is already known and how definitions, key concepts, characteristics and factors occur and how research is performed on teaching content for students with ID (see for example Munn et al. 2018).The study has been guided by two research questions: RQ1: What characterises different aspects of content displayed in research on teaching students with ID? RQ2: How is this content justified?
The (un)privileging of teaching content for students with ID Historically, students with intellectual disabilities (ID) have often been excluded from academic aspects of educational provision, or from mainstream education altogether (Cannella-Malone et al. 2021; V. Knight et al. 2010;Shurr and Bouck 2013;Spooner et al. 2011).Teaching content for this group has been dominated by functional life skills and rote learning, with a lesser focus on academic skills and meaningful learning (Berthén 2007;Göransson, Hellblom-Thibblin, and Axdorph 2016;Hord and Bouck 2012).It is only recently that schooling has increased the opportunities for students with ID to develop academic and more complex abilities (Browder et al. 2018;Moljord 2018).The history of schooling for students with ID displays that as late as in the middle of the 20th century, students in Sweden was deemed as partly educatable (Bagger 2022).This has developed over time and with an emphasis on learning life skills.
Including academic content in teaching for students with ID can, for example, improve opportunities in adulthood by expanding job opportunities and promoting independent living (Cannella-Malone et al. 2021).Hence, more recently, AC has been given an increasingly prominent role, with less focus on LFS (Moljord 2018).This comes with risks, however: 'If curricular research on functional life skills stagnates, curriculum policy and practice may fail to provide students with ID the skills necessary for social and practical adaptation in their communities' (Moljord 2018, 646).Ayres et al. (2011) support this with this quote from a parent: 'My son can identify Saturn, but he can't request a snack or even wipe his ass' (p.12).
In addition to the lack of clarity on what kind of teaching content should be privileged for students with ID, Browder et al. (2018) identify a methodological problem in studies on teaching and learning for students with ID: namely, that they are often carried out in closed special educational settings, which affects the possibility of drawing wider conclusions and generalising results.Research often focuses on the outcome of AC or LFS teaching using specific strategies in small-scale scenarios in alternative or inclusive classroom settings (Moljord 2018).Students' academic outcomes in mainstream or special settings are indeed explored, but without delving into or explaining the specific characteristics of these settings (Klang et al. 2020).In sum, there is a lack of clarity on how teaching content is privileged (what), the reasons for the selection (why) and connection to teaching (how).We contribute by scrutinising how this occurs in research to better understand how content are presented and (un)privileged.

Theoretical underpinnings
The research design consists of a didactical framework to analyse the interrelationship between teaching content, teacher, and learner.This framework allows for the understanding of teaching content in terms of how didactical questions are embedded in, construct, and reconstruct the content, the student, the teacher, education, society, and the wider world.More precisely, two aspects of didactical theory were adopted: the didactical triangle and the didactical questions (Gundem 2011;Hudson 2003Hudson , 2007)).The didactical questions provide a framework through which to scrutinise the didactical choices made regarding what content ought to be learned, why it is important, and how this content is represented in the classroom.In the field of didactics, substantial emphasis is placed on why (also in this study) the content is significant for the student.The reason for this is that the 'why' mirrors the rationale that substantiates the value inherent in the content and teaching (Klafki 1995).Hence, these rationales and justifications of the content represented in the classroom can, in turn, reveal how actions taken aim towards the future and what kind of understanding there is of the student and their knowledge or progression.
The didactical triangle take into account the complex interrelatedness that constitutes the teaching and learning setting between the teaching content, the student, and the teacher.Öhman's (2014) didactical triangle model is extended (see Figure 1).This adds school and societal aspects to the teaching and learning setting, but also embeds a sustainable development perspective.Consequently, both AC and life LFS in teaching for students with ID are understood in this article in terms of an extended didactical triangle (Öhman 2014); that is, teaching and learning are seen to be influenced by the wider schools and society and by the need for sustainable development (Öhman and Sund 2021).This allows for a perspective on teaching content that goes beyond the interrelatedness of teacher, student, and content by also recognising their interrelatedness with the school, society, and the sustainable development goals (SDG 2015).

Procedure for selection
The review was conducted in December 2022 following a search in the database Education Resource Information Center (ERIC).The justification for advocating this database was to target articles on education.The keywords intellectual disabilit* in combination with teaching, were used in a search in the abstract, title, keywords and topics fields.Limitations added were 'peer reviewed', 'English', and 'full text articles', which rendered 361 articles published between 1 January 2000 and 31 October 2022.Thereafter, the abstracts were read according to three inclusion criterias: the study depicts teaching content and teaching; and the study is situated in education for students in primary compulsory school and secondary school, for students aged 6-19.Articles that did not meet this criteria were deselected: We found orselves in a crossroad regarding the inclusion and exclusion criterias, as what we meant by a teacher needed to be defined for us to proceed.In the articles, what was intended with a teacher or a teaching occation, could not be taken for granted as it meant very different things.Consequently, we demarcated a teacher to refer to the person performing an act of teaching, regardless of education or occupation, and could also be a teacher assistant, or the researcher.These prequisites excluded a further 221 articles, leaving 106.These were then read in full according to the inclusion and exclusion criteria.This led to a further 56 articles being excluded and left 60 as the final sample for analysis (supplementary material, appendix).Much like what has already been reported by other scholars (for example, Browder et al. 2018;Klang et al. 2020;Moljord 2018), our 60 selected articles compiled a corpus displaying that the nature of this scope of research was dominated by small-scale settings with few students and teachers.Additionally, as concluded by earlier research, this kind of research was often carried out in arranged settings, such as a specific intervention or a selected group of students, and oriented towards students with multiple diagnoses.Often, this combination of diagnoses consisted of students with mild intellectual disabilities and autism.

Analytic procedure
We conducted a scoping review (Munn et al. 2018;Peters et al. 2020) to identify, organise and categorise how earlier research privileged teaching content for students with ID.The didactical questions -what, why, and how -were advocated to structure and guide the analysis and were applied as codes to grasp the content and its justification.The 'what' question provided answers regarding the subject of teaching, while the 'why' question provided justifications for this content.Additionally, we examined these questions in conjunction with the 'how' question to gain a more comprehensive understanding of the context in which the teaching content was presented and prioritised.
When approaching teaching from a didactical perspective, these didactical questions need to be considered in context.In other words, the context of education with and for students with ID demands its own considerations regarding why, what, and how content is privileged.Therefore, we categorised the selected segments of text using an adapted version of Moljord's (2018) framework on curricula and teaching of students with ID to which we added justification and adjusted content areas.Moljord's framework derives from the classical division of FLS (functional life skills) and CA (cognitive academics).Moljord refers to cognitive content as instructional techniques/interventions to enhance academic skills within traditional academic subjects (academic content), whereas we use them as two subcategories to academic content (AC).In our adapted framework FLS was developed to include the sub-areas: Communication, Healthcare and physical activities, and Social and interpersonal skills.Table 1 shows how we applied the content areas, subareas and justification of this content in the categorisation, with examples of interpretation.
After all selected segments were coded according to the didactic questions, and thereafter categorised in the developed framework on teaching content (what content?) and its justifications (why this content?),we performed an explanatory and interpretative analysis of teaching content for students with ID and its justifications by positioning the justifications within the extended didactical triangle.This implies that the why and what questions are understood and posed once more, but this time in terms of how they interacts with the school-level, societal-level, and global arena of sustainable development.Hence, teaching content for students with ID and its justifications have been studied beyond the contemporary conceptualisation of Functional Life Skills (FLS) and Academic content (AC).Furthermore, it goes beyond the interrelatedness of the classroom setting and aims towards a longer term and societal perspective of human rights and sustainability.

A new narrative of content for students with ID
In the following, the results are displayed first in terms of the distribution of content areas (what content?).This is followed by a presentation of justifications made in relation to these areas (why this content?).To give a brief overview of the frequency and direction of content areas, we initially present the variety of content areas of teaching which were identified in the selected studies: Academic 27; Independence 23; Cognitive 21; Social and Emotional 21; Communication 8; and Physical Health 5. Overlaps between these content areas often occurred, with some articles covering three or four content areas, e.g.Bassette, Communication is understood in a broad sense.Speech, language and giving voice are all part of this.We also include alternative ways of communicating and teaching content that targets the development of communication.'Many students with high support needs may be unable to use speech for expressive and/or receptive communication and may benefit from the use of alternative and augmentative strategies such as the use of graphic symbols . . .' (Stephenson et al. 2007, 56).

Self-care and independence
This content is needed for students to be competent to care for themselves and to make decisions in their own best interest.
Self-care also demands the ability to be selfaware of needs, wishes and strengths; to advocate for oneself also means that a person needs to know what he/she wants or needs and has the will to act on it.'Self-advocacy and self-determination include the abilities to select personal goals, plan steps toward goals, assess one's progress, make choices, and self-monitor and selfevaluate one's behaviours' (Kleinert et al. 2010, 16).

Health care and physical activities
This content is needed to facilitate students' abilities to care for bodily and physical health aspects, functions and training.
This area can be about physical growth and development, moto-sensory aspects of functioning, senses, and abilities to move or exercise physically.'During intervention, teachers applied paced prompting, differential positive reinforcement, and demand fading to gradually increase the quantity of novel foods the girl consumed' (Knox et al. 2012, p. 407).

Social and intrapersonal
This is needed to facilitate students' knowledge and skills to sustain relations with others.
This area implies that it is both important to know one's own feelings and be able to regulate them, but also to understand and be able to adjust to other people's needs, feelings, and expectations.'Elopement was defined as leaving the carpet area, wandering around the carpet area (knees or buttocks off the carpet), and lying or rolling on the floor' (Pennington et al. 2012, 4).

The complexity of didactical choices regarding what to teach
The justifications of the choice of teaching content (why) were often presented as multiple and complex.Our analysis displayed the following six thematic justifications 1) The content in its own right, 2) The content concerns skills and abilities, 3) The content concerns future studies, 4) The content concerns future work, 5) The content concerns life quality, and 6) The content concerns human rights.These justifications and their location in the extended didactical triangle are displayed in Figure 2. By 'location', we refer to the focal point of the six justifications or the most emerging emphasis of how the student, teacher and content is represented in the justification.Also, if these are framed in terms of their role in the classroom, the society, or the world, it is taken into account in our positioning of the justifications in the triangle.
When the given justification is the content in its own right, studies are focused on the 'Content' corner of the didactical triangle.Examples on these kinds of justifications from the selected articles can be made by articles within the Healthcare and physical activities area (Bassette et al. 2020;Knox et al. 2012), are included here.Learning to eat well and take care of one's health and well-being is a matter of importance in itself.
This kind of justification was also common in the area of Academic content, as it was argued to be important to learn how to read, write, count, do arts etc for its own sake.In these texts, no further arguments were declared beyond the learning the academic content itself, e.g.Pythagoras theorem (Creech-Galloway et al. 2013), word problems (Browder et al. 2018), to read (Swain, Lane, and Gast 2015) and to paint with quality (Waugh and Riddoch 2007).
The content aims to support students' abilities and skills was a justification placed closed to the 'Student' in the triangle.This justification was common in relation to AC and Cognitive content, represented for example as improving cognition and metacognition in mathematics (Karabulut and Özmen 2018), cognitive ability to acquire language (Alhassan and Osei 2020) and working with mental and cognitive characteristics, which could decrease repetitive behaviour or alter the mood of students (Bassette et al. 2020;Riddoch and Waugh 2003).This justification was also made in relation to the area Communication as that was considered a prerequisite for learning (Alexandersson 2011;Jorgensen and Lambert 2012).Self-care and Independence was claimed to be important for the development of skills and abilities to, for example, make well-founded decisions and develop independence (Pennington et al. 2012;Shogren et al. 2018).This relates to justifications related to developing new skills, such as brushing one's teeth properly (Kang and Chang 2020), knowing how to peel oranges (Aykut et al. 2014), having basic first aid skills (Eldeniz Cetin and Burak Bozak 2020), or ordering fast food at McDonalds (Mechling and Cronin 2006).These skills are obviously connected to wider society, but as the goals are in general individualistic they are therefore close to the student.
The two justifications The content aims towards future studies and The content aims for future work opportunities were positioned in the outer boundaries of the triangle, towards 'Society', with the goal to take part in new communities.This is seen as a common argument in relation to Academic content as this is needed for learning further academic content or future employment (for example, in Baker et al. 2015;Chung and Tam 2005;Hord et al. 2020;V. F. Knight et al. 2018;Wong 2021;Zisimopoulos 2010).These justifications were also made regarding Social and intrapersonal skills, as they were talked about as core in participation in studying, learning and functioning in a workplace (for example, in Jorgensen and Lambert 2012;Kleinert et al. 2010;Plavnick, Kaid, and MacFarland 2015).The content aims at quality of life and/or fulfilling human rights.These justifications are situated in the upper part of the model and aim for more abstract purposes.Although these justifications are close to the student, their focal point is a sustainable society and world.Justifications of human rights are further placed outside of the model, beyond impacting life quality, as they not only speak about the learning outcome for the students, but also refer to the global goal perspective.When this kind of justification was made regarding Academic content, the learning outcomes were depicted as leading to better participation in society (Herring, Grindle, and Kovshoff 2019;Karabulut and Özmen 2018;Lundberg and Reichenberg 2013;Orihuela et al. 2019;Saad et al. 2015).Communication was also an aspect of content to which justifications were made in relation to improved life quality and to society in terms of meaningful participation socially (Alexandersson 2011;Biggs et al. 2018;Jorgensen and Lambert 2012;Pennington et al. 2012).Justifications of the content self-care and independence were also made in terms of impacting life quality and human rights, as these were at times related to enhancing participation and improving relationships with others and society.This was seen, for example, in relation to learning how to read critically and to write with intent.To have access to and agency in advocating these skills is considered as important in life (Browder et al. 2018;Hord et al. 2020;Kleinert et al. 2010;Lundberg and Reichenberg 2013;Orihuela et al. 2019;Saunders, Spooner, and Ley Davis 2018;Wood, Browder, and Flynn 2015).
Justifications made from a human rights perspective was made through arguments of inclusion.For example, in Vlachou and Stavroussi's (2016), the teaching centres on problem-solving, with the overarching goal being to provide students with opportunities for social participation within inclusive settings.A similar context is observed in the work of Clarke et al. (2016), where the primary objective is the integration of students with intellectual disabilities into mainstream educational settings.Jorgensen and Lambert (2012) and Alexandersson (2011) also present different teaching contents with a shared emphasis on inclusion.Turning to Göransson et al. (2016) study of, the content revolves around the inclusion of students with ID in mathematics, challenging the conventional practice of excluding them from such academic domains".
In sum, the didactical question of why particular content is chosen, and the justification for this content, produces answers with different characteristics, which is illustrated in the text and the model.The justifications overall often are oriented towards, for example, future life and participation in society.

Intervention as the core of research and teaching
In addition to the six justifications, there were studies that were harder to place within a didactical framework.In these cases, the 'how' question in most cases concerned the research method or intervention, which in turn guided the teaching content.This is, for example, seen when the aim of the study is to compare different interventions, such as video prompting or least-to-most prompting (Aljehany and Bennett 2020) or direct instruction and strategy instruction (Blik, Harskamp, and Naayer 2016).In these cases, the class teacher was not involved in teaching or choosing content, and when involved, he or she rather followed the research methodology (Aykut et al. 2014;Karabulut and Özmen 2018;Mechling 2006;Mechling and Cronin 2006;Plavnick, Kaid, and MacFarland 2015;Shogren et al. 2018;Waugh and Riddoch 2007).

Discussion and implications
The current study set out to systematically explore how teaching content for students with ID is characterised, how it is (un)privileged in research and justified.The theoretical perspective of the extended didactical triangle was advocated to position the didactical choices and justifications made.In the following, conclusions are drawn, and the study discussed further in relation to the extended didactical triangle.Limitations of the study and implications for future research are also provided.A first recognition is that our own national, cultural and, theoretical understanding.Each of the studies are performed in its certain governing, national, cultural and, historical context and concepts as teaching, students and the policy or schooling of students with ID, might vary.
We conclude that the division of content into AC and LFS is not sufficient to capture the complexity of how teaching content is chosen and valued.Sub-areas exist within these two, and AC and LFS are often combined and intertwined.This speaks of a complexity inherited in how content for students with ID is chosen and valued.Öhman's (2014) extended triangle can serve to explore justifications of content and contributes to a didactical reflection that could grasp the complexity of choosing and valuing content.Justification has a practical consequences connected to them, and the same content could entail a diversity of instructions and learning outcomes, depending on its justifications.For example, if the focus of the content is cognitive skill, the design may result in one form of instruction, whereas if the justification of this content is future work or a sustainable world, the planning will differ.Furthermore, there seems to be a void when analysing the data through the lens of global 'challenges' (goals) in the expanded didactical triangle (Öhman 2014).Even though AC and LFS are crucial for the students' outcomes in adulthood, there are no justifications that highlight a sustainable world.Hence, content was in general described as important for the individual, but Environmental and Sustainable Education (ESE) or Human Rights Education (HRE) were not present in this.The closest indication of concern for the Sustainable Development Goals (SDG, UN 2015), was references to the goal of inclusion (Vlachou and Stavroussi 2016;Clarke et al. 2016;Alexandersson 2011;Göransson, Hellblom-Thibblin, and Axdorph 2016;Jorgensen and Lambert 2012) We do not suggest that SDG content should replace other categories, but rather that the justification and focus of SDGs as an aspect of content for students with ID is worthy of reflection in terms of its role when privileging content for students with ID.As displayed, teaching content played a secondary role in cases when interventions were the primary objective of the research.This could have ethical, methodological, and educational consequences and stress the importance of awareness of power relations involved in conducting research in terms of how teaching content and thereby students are privileged.We are not implying that intervention-driven research is less relevant or ethical; rather, we seek to reflect on prevailing educational research (also see Moljord & Browder) The absent or cloaked teacher and student The second conclusion is that it is rare with studies in which the teacher's choices and the everyday teaching of students with ID are visible.Therefore, many studies lack students' and teachers' experiences, although in some studies the methods are adapted to fit the characteristics of the students.The students are thereby positioned as the objects of research rather than active agents and subjects.Consequently, the social validity of these studies is low in terms of how students themselves experience teaching content, as for example producing swans out of towels (Atbasi and Tuğba 2020) or peeling an orange (Aykut et al. 2014).
To include students experiences, and thereby increase the social validity, would be valuable from an ethical, methodological, and educational perspective.We stress the need to empower students and teachers and to explore everyday teaching practice in context.This could add knowledge about the teachers' processes of making choices about content.This standpoint is in line with Shurr and Bouck (2013) and Browder et al. (2018) who question the research field's reliance on generalising experimental design studies.Also, Göransson, Hellblom-Thibblin, and Axdorph (2016) emphasise the importance of studying how the teaching and learning environments are constructed, including the relation between the teacher, the student, and the content.
In sum, studies often focused on interventions in limited areas of teaching content.Following from this, results and effectiveness of the research methods and their potential were put at the forefront, rather than the promises or challenges in the class-teacher's practice.We stress that it is of uttermost importance to also research the class-teacher's tacit knowledge on what kind of teaching content works and why.There is a risk that research produces artificial environments in which everything seems to work.This stands in contrast with didactical theory in which content and the students' needs and experiences are at the heart of how a teacher can and will plan their teaching (Gundem 2011;Hudson 2003).

Limitations and opportunities with the research design
In the theory of didactics, a teaching situation always consists of content, teacher, and the student (Gundem 2011;Hudson 2003).Importantly, the selected studies were often designed with purposes other than to exploring didactical aspects of teaching.Hence, our theoretical choice meant that we enhanced the focus on didactic aspects, and thereby ignored others, such as socio-political aspects, psychosocial perspectives, and aspects of culture.The reviewed studies often neglected two or all three corners of the didactical triangle: the teacher, the student, or/and the content, indicating that it is challenging to grasp the didactic elements of teaching for students with ID in research.
We call out for further studies that foreground the didactical relationship between content, the teacher, and the student.Especially since everyday instructional practices for students with ID and from the teachers and students perspective need more attention.Our hope for the future is that teachers and students are active agents within study design in research.This might be valuable to refine methods for data collection, to raise the interrelational validity of the analytic procedures, and might contribute to powerful knowledge in collaboration with teachers and students.

Disclosure statement
No potential conflict of interest was reported by the author(s).

Figure 2 .
Figure 2. The extended didactical triangle including justifications of teaching content for students with intellectual disabilities.

Table 1 .
Framework for analysis, its categorisation of content areas, justifications and definitions of these, and examples from the data.