Belonging and reciprocity amongst people with intellectual disabilities: A systematic methodological review

This methodological review compiles and assesses the approaches that have been taken to explore frequently overlooked or difficult to measure aspects of social inclusion. The specific focus is on how the concepts of belonging and reciprocity have been discussed and examined in the lives of people with intellectual disabilities. However, before describing the current review, it is necessary to situate it within a wider literature on social inclusion. Social inclusion takes on a multitude of meanings in the literature (Bates & Davis, 2004; Brown et al., 2015; Cobigo et al., 2012; Simplican et al., 2015), which has resulted in researchers approaching the topic from a variety of different angles and employing a wide range of methods (Simplican et al., 2015). While quantitative measures, such as the number and frequency of social contacts and communitybased activities, can be useful indicators of opportunities to establish connections in the community (Merrells et al., 2017a) and levels of community involvement (Simplican et al., 2015), they tell us little about social inclusion unless combined with an exploration of individuals' preferences (Bigby, 2012). Cobigo et al. (2012) argue that such objective measures should be accompanied by an investigation of subjective feelings of belonging to gain a full and meaningful understanding of social inclusion. ‘Without targeting this subjective element’, state Cobigo et al. (2012), ‘strategies Received: 27 January 2020 | Revised: 17 January 2021 | Accepted: 01 February 2021 DOI: 10.1111/jar.12881


| INTRODUC TI ON
This methodological review compiles and assesses the approaches that have been taken to explore frequently overlooked or difficult to measure aspects of social inclusion. The specific focus is on how the concepts of belonging and reciprocity have been discussed and examined in the lives of people with intellectual disabilities. However, before describing the current review, it is necessary to situate it within a wider literature on social inclusion.
Social inclusion takes on a multitude of meanings in the literature (Bates & Davis, 2004;Brown et al., 2015;Cobigo et al., 2012;Simplican et al., 2015), which has resulted in researchers approaching the topic from a variety of different angles and employing a wide range of methods (Simplican et al., 2015). While quantitative measures, such as the number and frequency of social contacts and community-based activities, can be useful indicators of opportunities to establish connections in the community (Merrells et al., 2017a) and levels of community involvement (Simplican et al., 2015), they tell us little about social inclusion unless combined with an exploration of individuals' preferences (Bigby, 2012). Cobigo et al. (2012) argue that such objective measures should be accompanied by an investigation of subjective feelings of belonging to gain a full and meaningful understanding of social inclusion. 'Without targeting this subjective element', state Cobigo et al. (2012), 'strategies aiming to improve social inclusion, integration and participation are likely to only achieve social exposure or the mere physical presence in the community ' (p. 80). While people with intellectual disabilities often have difficulty expressing these subjective feelings, it is crucial that efforts are made to help enable people to communicate their views.
The focus of this methodological review is on two elements that are often central to discussions of social inclusion-belonging and reciprocity-both of which require the exploration of peoples' perceptions of inclusion. This paper examines the qualitative and mixed-methods approaches researchers have taken to explore these concepts. This will expose the shortcomings and strengths of the methods used in previous research and provide a clearer sense of how belonging and reciprocity can be examined in a more comprehensive or rigorous fashion in future studies. However, before describing the methods adopted in this systematic review, it is important to have a basic understanding of how belonging and reciprocity fit within the broader discussion of social inclusion.

| DEFINING BELONGING AND RECIPROCITY
Social inclusion has often been viewed in relation to employment and independent living (Hall, 2005). While achieving these goals might lead to greater physical presence in the community, definitions of social inclusion should account for relationships, membership and belonging (Hall, 2017, p. 861). As Power (2013) states, belonging: takes the concept of social inclusion beyond narrow understandings and identifies it as not simply the promotion of the increased presence of marginalised persons in society, but rather that such people return to or begin to occupy valued social roles within society and community life. (p. 68) In their review of the literature on belonging and people with disabilities, Mahar et al. (2013) found that most definitions of belonging included feelings of being 'needed, important, integral, valued, respected or feeling in harmony with a group or system' (p. 1029). At its core, the cultivation of a sense of belonging is not about where people participate, but how they participate (Milner & Kelly, 2009).
In addition to general feelings of being valued and respected, the development of reciprocal relationships is important to fostering a sense of belonging (Mahar et al., 2013;Milner & Kelly, 2009), and the concept of reciprocity is included in many definitions of social inclusion. Overmars-Marx et al. (2014), for instance, describe inclusion as a 'reciprocal process' that involves the participation and commitment of everyone involved (p. 269), and Hall (2009a) concluded that the maintenance of reciprocal relationships was a core element of social inclusion.
Reciprocity is also a key component of how friendship is often conceptualised by people with intellectual disabilities (Bates & Davis, 2004;Callus, 2017) and has been found to act 'as an important way to challenge implied dependence' (Milner & Kelly, 2009, p. 56). However, while reciprocity is often found to be an important theme in studies on social inclusion, very little work has focused on reciprocity specifically. An exception to this is a study by Bredewold et al. (2016), which found that reciprocal relationships can develop between people with and without disabilities, but the common notion of what constitutes balanced reciprocity may need to be expanded to include different or seemingly smaller return gifts, such as 'happy smiles' (p. 547) or 'expanded horizons' (p. 545).
Belonging and reciprocity are central to discussions of social inclusion yet often remain unexplored in their own right. An important starting point is to examine how these concepts have been defined and operationalised in previous research. This review will seek to answer the following questions: (a) How have belonging and reciprocity been defined in studies exploring these concepts in the lives of people with intellectual disabilities? (b) What qualitative or mixed methods approaches have been used in these studies? and (c) What were the strengths and weaknesses of the approaches adopted? 2 | ME THOD

| Study design
This review took a systematic approach to identify and evaluate relevant papers, following the approach taken by Fryer et al. (2012) to conducting a methodological systematic review.

| Search strategy
The database search was intended to return papers focused on the social inclusion or community participation of people with intellectual disabilities. During the screening process, this initial pool of resources was narrowed down to studies looking specifically at belonging or reciprocity. The search was deliberately kept quite broad to make certain all relevant studies were returned. Guidance was sought from a university librarian to help refine the search strategy and ensure best practice was adhered to.

| Databases
Ten databases were searched as shown in Figure 1 Research) and reference lists of included papers was also conducted to identify any additional relevant studies.

| Search terms
Search terms were identified through a careful read of the literature and preliminary searches of the databases. It was not anticipated that belonging or reciprocity would be the primary focus of all included studies, so search terms were designed to encompass a broad range of concepts related to social inclusion more generally.
Relevant database-specific, phrase-indexed subject headings were also searched in all databases except Scopus, which does not provide a thesaurus. Search results were limited to peer-reviewed journal articles published since 2000 in English.

| Selection process
Search results were exported to EndNote, where duplicates were removed. Titles and abstracts were screened against the initial list of inclusion and exclusion criteria. Selected papers were then read in their entirety, and the full inclusion and exclusion criteria were applied.
The following inclusion and exclusion criteria were developed to identify empirical papers focused on how belonging and reciprocity were experienced by people with intellectual disabilities in settings and opportunities available upon exiting the school system: Inclusion criteria: 1. Primary research 2. Focuses on social inclusion or related concepts as they apply to people with intellectual disabilities.

Is a peer-reviewed journal article published in 2000 or later in
English.
4. Focuses on adults or young people aged 16 and over.

Uses qualitative or mixed methods.
For full-text screening, the following inclusion criterion was added: 1. Attempts to measure or describe experiences of (not) belonging or (a lack of) reciprocal relationships. 2. Has a primary focus on the participation or inclusion of family members or supporters and experiences of people with intellectual disabilities are disregarded.
3. Focuses on the training of supporters or clinicians or on the provision or evaluation of services.

Focuses on an intervention that does not have increasing social
inclusion or participation as a primary aim.

Focuses on people's opinions or feelings about including peo-
ple with intellectual disabilities in mainstream or community settings.
6. Is clearly focused on other disabilities with a low likelihood that half of participants would have intellectual disabilities, unless otherwise specified.
7. Focuses on policy or policy implementation.

Focuses on inclusion within primary or secondary school
classrooms.
For full-text screening, the following exclusion criterion was added: 1. It is not specified that at least half the primary participants have intellectual disabilities.
Titles, abstracts, and full-text articles were screened independently by two researchers, and conflicts were discussed until agreement was reached in each instance.

| Quality appraisal and data extraction
Quality appraisal was carried out to provide a comprehensive overview of the conduct of the studies and the level of description provided in the papers. As the function of the quality appraisal was to provide discussion points rather than eliminate papers from this review, papers were not scored. Because quality appraisal was conducted purely for descriptive purposes, the process allowed for the development of a quality appraisal checklist combining elements from three frequently used quality appraisal tools.

friendship dyads (8 individuals: females and males aged 28-49 years)
from a L'Arche community in which one friend had intellectual disability and one did not; 1 key informant included to facilitate understanding of nonverbal communication of participant with severe intellectual disability three categories were identified: 1) contours of friendship, 2) facilitating friendship, and 3) L'Arche--a community context; friendships between people with and without developmental disabilities occur and can be meaningful and reciprocal 51 adults with intellectual disabilities and intermittent to limited support needs (29 females and 22 males aged 16-52 years), 12 of whom participated in interviews (6 females, 6 males); parents, teachers, and work supervisors completed questionnaires the modified Loneliness Scale was found to be reliable and valid; interviews revealed distinct differences in the experiences of the 'most lonely' and 'least lonely' participants, including how the groups described their friendships; the expectations they had of their friends; and their experiences establishing, negotiating, and maintaining friendships central participant was a 20-year-old female with severe intellectual disability; 14 of the central participant's social network members were interviewed (4 family members, 8 support workers, and 2 peers with intellectual disabilities) the participant's social interactions could be summarised by 3 primary roles (lioness, anxious child and entertainer); aside from family, her social network was primarily made up of paid and domain-specific relationships; interactions could be both challenging and valued by the people in her social network 6 central participants with intellectual disabilities who communicated at a symbolic, non-linguistic level (3 females and 3 males aged 20-44 years); 57 people who had a positive relationship with a central participant (22 family members, 29 paid workers, and 6 peers), 51 of whom were interviewed social interactions were situated within a shared moment; two themes characterised interactions in shared moments: 1) having fun and 2) hanging out 8 heterosexual couples (16 individuals: 8 females and 8 males aged 26-65 years) where both members of the relationship had intellectual disabilities close personal relationships provided many benefits to participants; five themes were identified: 1) comradeship-being together is what matters, 2) the experience of happiness and contentment, 3) mutual support and complementary reciprocation, 4) coping with the ups and downs of relationships, and 5) continuation and commitment 18 adults with mild intellectual disabilities who had worked 3 days/week at the same workplace for at least 6 months (7 females and 11 males aged 21-56 years) factor analysis revealed two primary views on work and social integration: 1) work as participation and 2) work as structure; interviews revealed that supported employment contributed to self-development and was preferred over placements in day centres 12 adults with intellectual disabilities who were involved in a selfadvocacy group (all but one aged 55 years and over) three main themes were identified: 1) a sense of belonging, 2) social connections, and 3) doing things that matter; involvement in selfadvocacy groups can help further the social inclusion of people with intellectual disabilities 74 primary participants with intellectual disabilities from 3 regions of Ontario, Canada (30 females and 44 males aged 21-59 years); 60 people who supported a primary participant were also interviewed benefits of both paid and volunteer work included: enjoyment, a sense of belonging, and feelings of making a contribution; inclusion was promoted in the workplace through frequent and ongoing contact with others, shared workplace experiences and overlapping routines, and having the sense that someone in the workplace would provide a listening ear 31 adults with intellectual disabilities enlisted in military service (12 females and 19 males aged 21-30 years); 36 family members (primarily parents); 28 military commanders or career soldiers in charge of participants with intellectual disabilities level of inclusion varied; four social network groups were identified that varied in closeness and reciprocity, each of which played an important role in the social inclusion of participants; relationships were often formed but tended to be limited to the base 10 adults with moderate intellectual disabilities (3 females and 7 males aged 19-48 years) who were members of a social group two core themes were identified: 1) supported engagement fosters well-being and 2) developing social belonging and connectedness; the social group helped counter loneliness, expand friendship circles and social life, provide a greater sense of well-being, and reverse a largely sedentary and isolated lifestyle (Continues)  Table 1.
Quality appraisal ratings were completed independently by two reviewers. All conflicts were discussed until agreement was reached.
Data were then extracted to compile detailed descriptions of the theories and procedures used in each of the studies.

| RE SULTS
Search results are presented in Figure 1, and results from the quality appraisal are shown in Table 1(a-c). An overview of the 17 papers selected for inclusion is provided in Table 2(a-c), and additional study characteristics are provided in Table 3(a-c). Overall, the selected studies encompassed a wide range of research aims and study designs. Each of the papers discussed belonging or reciprocity at some point; however, as a group, they rarely had a primary focus on these concepts or the intent to explore them from the outset of the research. All studies were conducted in high-income countries.
The 17 selected papers were grouped into three broad categories based on how reciprocity and belonging featured in the research, each of which will be presented in turn: (a) reciprocity in relationships and social interactions; (b) belonging within a specific setting; and (c) experiences of belonging in the wider community. Within each of these categories, a summary of how belonging or reciprocity was incorporated will be presented, followed by a description of the methods adopted. After this, the paper will turn to a more critical discussion of the strengths and weaknesses found across this body of research.

| Reciprocity in relationships and social interactions
Five papers explored the interpersonal relationships and social interactions of people with intellectual disabilities and are presented in Table 2a (Johnson et al., 2010(Johnson et al., , 2012Lafferty et al., 2013;McVilly et al., 2006;Pottie & Sumarah, 2004). Each of these papers included some discussion about the reciprocal nature of the relationships or interactions under study. Two of these papers (Johnson et al., 2010(Johnson et al., , 2012) came from the same study, meaning four unique studies were identified.
Three of these five papers spoke explicitly of reciprocity. Pottie and Sumarah (2004)  21 adults with intellectual disabilities from five locations in Scotland social inclusion as it is conceptualised in policy does not fully recognise the rejection people often face in inclusive spaces or take into account individual preferences; people with intellectual disabilities have responded to discrimination by self-excluding and actively creating safe spaces 14 young adults with mild or moderate intellectual disabilities (7 females and 7 males aged 22-35 years) seven themes were identified: 1) living accommodations and transportation, 2) work and volunteer experiences, 3) involvement in activities, 4) relationships and interactions, 5) sense of belonging, 6) social roles, 7) influential factors; participants had varied experiences of social inclusion which were attributed to a range of factors 21 adults with mild or moderate intellectual disabilities from one county in Sweden (11 females and 10 males aged 33-48 years) quality of life is characterised by subjective well-being; the experience of well-being consisted of five themes: 1) social adult status, 2) control of life, 3) personal safety, 4) social belonging, and 5) self-chosen solitude 7 central participants with mild or moderate intellectual disabilities who were members of an organisation that supported people with intellectual disabilities (aged 21-48 years); 74 attendees of the community photovoice exhibition completed surveys six themes were identified, the first two of which were discussed at length: 1) a desire for community membership and to achieve a sense of belonging and 2) a desire for independence and to live independently; a survey of the community photovoice exhibition attendees provided positive feedback, but nearly half of respondents were friends or family of participants 10 young adults with intellectual disabilities (5 females and 5 males aged 19-24 years) who had experienced long-term community-based coordination and services two main themes were identified: 1) segregated, excluded, and treated like an outcast in my community; and 2) challenges in experiencing, initiating, and maintaining peer friendships 24 adults with intellectual disabilities (9 females and 15 males aged 20-61 years) who were involved in a self-advocacy organisation two main themes and six subthemes were identified: 1) meaning of belonging: i) belonging in relation to place, ii) belonging as being part of a community, iii) belonging as having relationships and iv) belonging as identity; 2) barriers to belonging:: i) prejudice and ii) bullying 12 adults with intellectual disabilities (4 females and 8 males aged early 20 s to late 50 s) associated with self-advocacy groups and community organisations in Toronto, Canada three major themes were identified: 1) going shopping--negotiating autonomy and responsibility; 2) shopping and sociability; and 3) presence, participation, and belonging; shopping was a key activity in participants' weekly routines and created opportunities for autonomy and encounters with others study (Pottie & Sumarah, 2004), stated that qualitative field research was employed. The presentation of data in this paper was suggestive of a narrative approach. Four of the five papers mentioned the use of methods that allowed the researchers to observe participants' relationships or interactions with others. This was accomplished through jointly conducted dyadic interviews and extensive observation.
According to Morgan et al. (2013), dyadic interviews promote interaction between participants, which allows for the stimulation of ideas that may be overlooked in individual interviews. In studies described by Lafferty et al. (2013) and Pottie and Sumarah (2004), dyadic interviews allowed for a more in-depth understanding of participants' relationships, which perhaps enabled the reciprocal nature of these relationships to emerge and be explored. However, Lafferty et al. (2013) did note that one partner tended to dominate the interview, an issue that has been raised in previous critiques of this approach (Booth & Booth, 1994). To help counteract this, individual follow-up interviews were also carried out to gain the perspective of each partner on their own (Lafferty et al., 2013). This was illustrated particularly well through fieldnotes depicting an exchange between two people in a close relationship whose communication did not depend on words (Johnson et al., 2011, p. 268).
The final study to touch upon reciprocity (McVilly et al., 2006) began by piloting a quantitative scale of loneliness. Subsequent interviews explored how loneliness was experienced by the least and most lonely survey respondents. This was the only study in this group that relied entirely on participants' self-reports of relationships.
As illustrated by Table 3a, only one paper mentioned providing accessible study information to participants at the outset. It was also notable that three papers did not fully describe the contexts (sites, settings, and timeframes) in which data were collected, and none fully explained the relationship between researchers and participants (see Table 1a). However, it should be clarified, that an omission of these details in the text does not mean that the researchers did not address these points; it simply means that the information was not presented in the paper.

| Belonging within a specific setting
Belonging was mentioned in reference to a specific context-such as a workplace or social group-in five studies (Cramm et al., 2009;Frawley & Bigby, 2015;Lysaght et al., 2017;Werner & Hochman, 2017;Wilson et al., 2017). The details of these studies are shown in Table 2b. While each paper spoke overtly of belonging, none pro-

| Methods adopted
A phenomenological approach was taken in two studies (Werner & Hochman, 2017;Wilson et al., 2017), Q methodology was used in a third (Cramm et al., 2009), and a fourth paper (Lysaght et al., 2017) At least one person with intellectual disability interviewed as part of data collection process?

Primary participant with intellectual disability interviewed as part of data collection process?
Explains how data collection process was adapted for participants with intellectual disability? stated that a grounded theory approach was adopted. The final study (Frawley & Bigby, 2015) was described as 'inclusive research'

Interview schedules
and employed an exploratory qualitative approach.
The study by Cramm et al. (2009)

took a very different ap-
proach than the other studies in this review. The researchers utilised Q methodology, which according to McKeown and Thomas (2013), 'brings qualitative research into the quantitative realm' (p. 2).
Participants were first asked to complete a Q-sort, whereby they rank-ordered a series of 22 statements derived from the literature on social integration as it pertained to the workplace. The Q-sort was followed by individual interviews; however, the authors provided very little discussion of these interviews and did not describe how the data were analysed.
Two studies used a combination of interviews with primary par- As shown by Table 3b, only one of the five papers mentioned that accessible study information was provided to participants. It was also found that just two papers in this group fully described the contexts in which data were collected, and only one adequately considered the relationship between researchers and participants (see Table 1b).
Furthermore, two papers did not describe the qualitative data analysis in enough detail to demonstrate that it was sufficiently rigorous.
Two of these studies drew from the framework of belonging posited by Antonsich (2010), in which belonging is organised: around two major analytical dimensions: belonging as a personal, intimate, feeling of being 'at home' in a place (place-belongingness) and belonging as a discursive resource which constructs, claims, justifies, or resists forms of socio-spatial inclusion / exclusion The study by Hall (2009b) used the author's own conceptualisation of social inclusion, which emerged from a qualitative metaanalysis (Hall, 2009a). Social inclusion was defined as 'being involved in activities, developing and maintaining reciprocal relationships, and having a sense of belonging' (Hall, 2009b, p. 25). A sense of belonging was subsequently identified as a major theme when describing how social inclusion was experienced by young adults with intellectual disabilities.
A further two papers featured belonging in the results. The study by Umb-Carlsson and Lindstedt (2011), found a sense of social belonging to be a major component of quality of life from the perspectives of people with intellectual disabilities. Through their photovoice project, Schleien et al. (2013) found that participants desired a sense of belonging, which was evidenced by participants speaking of the places they felt welcomed or accepted.
The two remaining papers did not feature belonging as prominently. One of these (Merrells et al., 2017b) briefly mentioned a sense of belonging in both the introduction and results sections, but the authors never defined the concept or discussed it in any detail.
The final paper (Hall, 2004) offered a critique of existing definitions of social inclusion and social exclusion to contextualise the research.
While the concept of belonging was never discussed explicitly in this paper, many participants' narratives touched on topics related to feeling accepted or welcomed.

| Methods adopted
Three of these studies adopted a phenomenological approach (Hall, 2009b;Merrells et al., 2017b;Umb-Carlsson & Lindstedt, 2011), two utilised participatory approaches (Schleien et al., 2013;Wilton et al., 2018), and one used a narrative approach (Hall, 2004). The remaining paper (Strnadová et al., 2018) failed to describe a specific study design, but stated that inductive content analysis was used to analyse the data. All seven papers incorporated either individual or group interviews with primary participants with intellectual disabilities as part of the data collection process. Hall (2004)  The final two studies adopted more participatory approaches. Schleien et al. (2013) used photovoice, which has been described as 'a creative form of participatory action research' (Brake et al., 2012, p. 45). This method uses photography and group discussion to promote critical reflection and conversation about the strengths and concerns within a community (Wang & Burris, 1997, p. 370). In their project, Schleien et al. (2013)  workshops. The authors noted that their study design fell short of participatory action research, but they still strove to actively involve participants throughout much of the research process.
Only two of these studies stated that participants were provided with accessible study information as shown by Table 3c. In addition, only two fully described the context in which data collection took place, and only two adequately considered the relationship between the researchers and participants (see Table 1c).

| Conceptualisations of belonging and reciprocity
While each of the papers in this review contained some discussion of belonging or reciprocity, these concepts were rarely explored from the outset or defined. The relative omission of belonging and reciprocity from the literature is problematic because they have both been identified as key components of social inclusion (Hall, 2009a;Overmars-Marx et al., 2014), making them important constructs to examine.
Furthermore, of those papers that did strongly feature belonging and reciprocity, almost none provided clear definitions for these terms, leaving the reader to infer what was meant by the authors. While it is recognised that authors cannot be expected to define every concept mentioned in the text, the general lack of clear conceptualisations of belonging and reciprocity across this literature was striking.
A coherent conceptualisation of belonging was only adopted in two papers (Strnadová et al., 2018;Wilton et al., 2018). An additional five papers included belonging within the major research themes yet failed to provide a clear definition of the concept. This is perhaps unsurprising, as Mee and Wright (2009) pointed out: 'Sometimes, belonging is at the centre of the analysis but, more often, it is used in a way that implies a common understanding of what belonging is and why belonging is important' (p. 772), to which they added, 'no such common understanding exists' (p. 772).
The two papers that defined belonging both drew from the framework developed by Antonsich (2010). In the remaining papers, belonging tended to be described in relation to being welcomed, accepted or appreciated, which certainly resonates with Antonsich's framework. However, by providing very little in the way of definition, these papers generally assumed readers had a common notion of what belonging was.
Across this body of work, belonging was mentioned in relation to specific settings, such as a workplace or social group, as well as to more general contexts, such as a neighbourhood or community.
Through their scoping review of literature on sense of belonging and disability, Mahar et al. (2013) similarly found that the scale and context to which belonging was ascribed varied widely. This led the authors to emphasise the importance of specifying the 'external referent that serves to ground the individuals' subjective perceptions' (Mahar et al., 2013(Mahar et al., , p. 1030. Mahar et al. (2013) argued that 'because of the possibility that a sense of belonging may be multifaceted and conflicting, depending on the external referent, a global measure will not have practical applications and may be misleading' (p. 1030). Belonging is highly context-dependent and can only be understood in reference to a specific group, time, and place. For instance, belonging is likely to mean something very different in relation to a specific structured social group with regular attendees, such as that described by While at least some attempts were made to explore and conceptualise belonging, there was a marked lack of research conducted on reciprocity, and limited attempts were made to define the concept. This is a critical oversight considering that reciprocity has been found to be central to descriptions of friendship by people with disabilities (Bates & Davis, 2004;Callus, 2017;Milner & Kelly, 2009) and a key component of both social inclusion (Hall, 2009b;Lysaght et al., 2017) and belonging (Mahar et al., 2013).
Across these studies, the concept of reciprocity tended to arise through discussions of interpersonal relationships or social interactions, and studies describing reciprocity often made mention of mutual enjoyment or exchanges.
While only one paper mentioned that reciprocity should not be contingent upon equal exchanges (Johnson et al., 2010), it is important to reiterate that point here. As bell hooks (2009)

| Methods used across this research
The number of qualitative studies in intellectual disability research has been shown to be increasing over time (Beail & Williams, 2014).
However, between 2009 and 2011, it was found that the range of research methods employed in these studies was limited, with the majority relying on semi-structured interviews (Beail & Williams, 2014). Across the 17 papers in this review, individual interviews were likewise identified as the primary means of data collection. This heavy reliance on participants' abilities to express themselves may have excluded many people from taking part in this research and contributed to the fact that only two studies in this review included participants with severe intellectual disability (Johnson et al., 2010(Johnson et al., , 2012Pottie & Sumarah, 2004).
Despite the extensive use of individual interviews, the range of methods adopted by researchers did appear to be diversifying in recent years, with four papers mentioning the use of group interviews, three including participant observation, two making explicit use of dyadic interviews, two employing photographic methods, and one using go-along interviews. Studies using observation and dyadic interviews allowed researchers to witness exchanges between primary participants and their close social contacts, which was particularly important to the exploration of reciprocity. Through direct observation, researchers could document the subtle or often seemingly unremarkable reciprocal actions of participants.
The studies using photography (Schleien et al., 2013;Wilton et al., 2018)  However, regardless of methods adopted, some issues and omissions relating to recruitment and data collection procedures were identified across these 17 papers. Before discussing these shortcomings, it is important to reiterate that omissions may be due to constraints imposed by word limits. Furthermore, some authors While it is recognised that many of these studies were of high quality, the absence of key information across the papers included in this review is notable and warrants discussion.
Of the 16 studies to conduct group or individual interviews with participants with intellectual disabilities, only seven papers indicated whether a supporter was, or could be, present during interviews. The importance of providing this information should not be overlooked. Jointly conducted interviews have been found to allow ideas and topics to surface that may not emerge otherwise (Booth & Booth, 1994), and supporters have been included in group interviews to help build trust and help participants express themselves (Hall, 2004). However, the relative power of supporters can influence what participants say (Llewellyn, 2009), and there may be a tendency for some supporters to dominate interviews (Booth & Booth, 1994). Therefore, the presence or absence of others should be clarified, as it is likely to have an impact on the data collected.
Researchers should also detail the steps taken to make the research accessible to participants. It has been recommended that people with intellectual disabilities be provided with study information in advance, giving them plenty of time to develop questions and discuss it with others, and that study information be provided in formats accessible to potential participants (Andre- Barron et al., 2008). Only four papers in this review described how study information was made accessible. Without this detail, it is impossible to assess the degree to which participants were truly informed about the studies in which they took part. This is not to say that research should only attempt to include participants who are able to provide informed consent on their own behalf, but that care should be taken to explain studies to all potential participants and involve them in the process of consent as fully as possible.
Across these papers, it was also found that the contexts in which data were collected and relationships between researchers and participants were seldom fully explained. By omitting this information, the authors failed to provide the reader with a complete understanding of the data or demonstrate how the researchers acted as valid and reliable tools of data collection. As Booth and Booth (1994) stated in their reflections on conducting interviews with people with intellectual disabilities: 'ultimately, in this type of research, the validity of the data is the stuff of the relationship between the interviewer and the informant' (p. 421).

| Limitations
This systematic review has several limitations. The search was

| CON CLUS ION
While each of the 17 papers in this review touched on belonging or reciprocity, very few defined these concepts or explored them in much depth. The papers also frequently omitted important details concerning recruitment and data collection. These shortcomings should be addressed in future research to reveal more fully how belonging and reciprocity are experienced by people with intellectual disabilities and produce a sound and robust literature on these concepts. This work is vital given how prominently belonging and reciprocity feature in discussions of social inclusion and could lead to communal and societal level changes that enable people with intellectual disabilities to lead fuller lives.

ACK N OWLED G EM ENTS
We would like to thank Sophie Westrop (Institute of Health and Wellbeing, University of Glasgow) for her assistance with quality appraisal and the three anonymous reviewers for their helpful comments.