Open Research Online The impact of selfadvocacy organizations on the subjective wellbeing of people with intellectual disabilities: A systematic review of the literature

Background: A high sense of subjective well-being has been associated with more prosocial behaviours, better health, work productivity and positive relationships. The aim of this systematic review was to explore what impact self-advocacy has on the subjective well-being of people with intellectual disabilities. Method: The authors reviewed articles focusing on the perspectives of adults with intellectual disabilities engaged with self-advocacy groups. Searches were performed in PsychINFO, Web of Science, SCOPUS, MEDLINE and CIHNL databases, resulting in 16 articles meeting the inclusion criteria. A framework synthesis approach was used to extract data deductively based on the Dynamic Model of Wellbeing. Results: While self-advocacy has a positive impact on all domains of the Dynamic Model of Wellbeing, negative impacts associated with participation in a self-advo-cacy group were also reported. Conclusions: The benefits of participating in self-advocacy groups on the well-being of individuals with intellectual disabilities outweigh the disadvantages.

TILLEY ET aL. are inadequate in determining the progress of societies and one's quality of life (OECD, 2013). Instead, it is necessary to consider the subjective well-being of members of society. Not only is high subjective well-being a desirable outcome, it benefits one's health (Chida & Steptoe, 2008), income (Diener, Nickerson, Lucas, & Sandvik, 2002), work productivity (Oswald, Proto, & Sgroi, 2015) and social behaviour (Aknin, Sandstrom, Dunn, & Norton, 2011).
Self-advocacy for people with intellectual disabilities emerged in Scandinavia, North America and the UK in the 1980s (Buchanan & Walmsley, 2006) as institutions were closing. Almost four decades later, the backdrop has shifted to include equality legislation in many countries (Soldatic & Johnson, 2019), changed attitudes, international commitments to citizenship (Department of Health, 2001;United Nations, 2006), exposure of institutional abuse and economic austerity. However, in the UK at least, self-advocacy groups are in many areas seen to be under threat-although no systematic research into this has been published since 2012 (National Forum, 2011). Studies of the history of the self-advocacy movement in Denmark (Bylov, 2006), England (Buchanan & Walmsley, 2006) and in the Australian state of Victoria (Henderson & Bigby, 2016) indicate that self-advocacy evolves over time in response to a variety of external factors, including funding, policy context, availability of suitable support staff and relationships with other advocacy organizations. Initially, there was significant interest in whether self-advocacy groups were independent of services (Crawley, 1988). An early focus was also pedagogic-how to run good meetings, or how to "stick up for yourself" for example (Buchanan & Walmsley, 2006;Simons, 1992). In Victoria, its focus migrated from energetic political campaigning in the 1980s to an emphasis on improving the lives of those inside the organization in the 2000s (Henderson & Bigby, 2016, p. 55). In Denmark, Bylov (2006) argues that there was a maturing of the movement, enabling it to free itself from the parents' organization, which had given it birth and early nurturing. Relationships with parents' organizations have surfaced as a major and fraught issue in the UK (Walmsley, 2016), as well as globally (Walmsley & Jarrett, 2019). In the recent context of UK austerity policy, Power and Bartlett (2018b) and Walmsley (2020) have observed that self-advocacy is morphing once more, this time in response to the retreat of the welfare state which has left many people with intellectual disabilities searching out new spaces of support and belonging.
Many definitions of self-advocacy can be found in the literature, but common-and enduring-components include the notion of speaking up for yourself or others, standing up for your rights, making choices, being independent and taking responsibility (Ryan & Griffiths, 2015;Simons, 1992;Williams & Shoultz, 1982). Selfadvocacy has been described as "a space in which people with intellectual disability can develop not only their confidence, skills and leadership capacity, but also a collective identity, providing an essential foundation for grassroots activism" (Tilley, 2013, p. 470). In this way, self-advocacy can be seen as an activity and a process that is both personal and political (Frawley & Bigby, 2015). However, it is important to note that the existing literature on self-advocacy suggests that it is largely confined to people with mild or moderate intellectual disabilities (Walmsley & Downer, 1997); it has been dominated by men and, in the United Kingdom and United States, by people with Caucasian backgrounds (Caldwell, 2011;Goodley, 2000). This has to be born in mind when considering its impact on well-being.
In this systematic review, the authors explore what impact self-advocacy has on the subjective well-being of people with intellectual disabilities, as measured by themselves. The research question guiding this review was: "What difference does self-advocacy make to self-advocates' subjective sense of wellbeing?" The review examines the published academic research on self-advocacy. For the purposes of this review, self-advocacy is understood specifically as an organized activity in which people with intellectual disabilities participate in a structured self-advocacy group or organization. This review did not include papers that are focused solely on self-advocacy as the development of new skills (i.e. self-advocacy as a learning process). The review was underpinned by the Dynamic Model of Wellbeing, described below (Abdallah et al., 2011).

| Conceptual framework
The Dynamic Model of Wellbeing, developed by the New Economics Foundation-or NEF-integrates different theoretical approaches to wellbeing into one single coherent explanatory model (Abdallah et al., 2011).

It emerged from the UK Government's 2008 Foresight Project on Mental
Capital and Wellbeing, which tasked NEF's Centre for Wellbeing to consider the relationship between different approaches to measuring wellbeing (e.g. objective indicators; eudaimonic accounts; hedonic accounts; evaluative accounts) and policy-making. NEF's Centre for Wellbeing concluded that these different (and often competing) approaches to measuring well-being could be brought together "to depict the emergence of well-being through a dynamic system" (Michaelson, 2013, p. 100). The resulting model outlined the critical feedback loops that exist between emotions, functioning and external conditions. This has practical implications for policy-making as it emphasizes the importance of improving people's material conditions and their personal resources in F I G U R E 1 The Dynamic Model of Wellbeing [Colour figure can be viewed at wileyonlinelibrary.com] order to positively affect well-being. For the purposes of this review, the Dynamic Model provided us with a practical and accessible framework, grounded in theory and empirical research, to help us identify the ways in which self-advocacy might influence well-being.
Well-being is understood in the Dynamic Model as "flourishing": feelings of happiness, joy, contentment and satisfaction that are achieved when sufficient personal resources and positive external conditions are in place to enable good functioning and satisfaction of needs (Figure 1). The model describes how: an individual's external conditions-such as their income, employment status, housing and social context-act together with their personal resources-such as their health, resilience and optimism-to allow them to function well in their interactions with the world and, therefore, experience positive emotions. The model shows how different aspects of our wellbeing interlink and how improvements in one area influence other parts of an individual's experience (NEF, 2019).
The four key domains of the Dynamic Model (personal resources; external conditions; good functioning and satisfaction of needs; and good feelings day to day and overall) provided the analytic framework for this review. When reviewing the included papers, the authors identified examples of well-being that corresponded with these four domains.

| Search strategy and eligibility criteria
The method used for the review aligns with the recommendations on preferred reporting items for systematic reviews and meta-analyses Papers were excluded if (a) they were discussion papers; (b) they focused on self-advocacy as a learning process only; c) they included participants with specific learning difficulties ("dyslexia," "dyscalculia," "dyspraxia") and not intellectual disabilities.

| Study selection
The asterisk symbol was used in many of the keywords/phrases to account for suffix variations of keywords. A total of 1,170 articles were identified from the electronic search. 91 duplicate articles were removed, and a further 657 articles were deemed irrelevant and removed. 422 abstracts were examined against the eligibility criteria independently by the first and second author, and 382 were excluded. Cohen's kappa was used to calculate inter-rater reliability, with the average inter-rater reliability score at this stage of screening being high with κ = 0.7737. All disagreements were discussed and resolved.
In the second stage, the first and the second author independently examined the full text of 40 included articles. Inter-rater reliability for this stage was very high with κ = 0.8977. 16 articles met the criteria for this study. Figure 2 details the search strategy and results.

| Inclusive approach to systematic review
When conducting this systematic review, the present authors used an inclusive research approach (Walmsley & Johnson, 2003). This was a critical and innovative element of this systematic review, which the present authors included to gain the insights and perspectives of a person with experience of self-advocacy. It corresponds with recent calls for increased co-construction of research agendas relating to self-advocacy (Fenn & Scior, 2019), and for transparency of the co-authoring process (Strnadová et a., 2018).
The fifth author is a self-advocate who has spent over 20 years working in a self-advocacy organization, supporting other self-advocates. She brought experiences not only of her own, but also of other self-advocates. Her contributions add a different and important perspective.
The process was as follows. The academic researchers undertook the systematic review. They then wrote the first draft of this article. The second author prepared an easy read version. Using this version, the second and fifth author discussed and commented on the review findings. The meeting was audio recorded. This discussion had two major outcomes.
First, the fifth author acknowledged the relevance of the Dynamic Model of Wellbeing Model's four domains but said that the visual representation (see Figure 1) was confusing for her. She suggested a different layout, which would better express well-being in relation to self-advocacy and better reflect the findings of this review (see Figure 3).
Second, her reflections were included in the paper's Discussion section, including direct quotations.

| Quality assessment
In order to assess quality of the studies, the present authors used The Standard Quality Assessment Criteria for Evaluating Primary Research Papers from a Variety of Fields (Kmet, Lee, & Cook, 2004).
This reliable tool designed for systematic reviews is unique in that it which the relevant criteria were met, with scores < 55% interpreted as weak, 55%-75% as moderate and > 75% as strong. The present authors agreed that 13 articles were strong, 2 were moderate and 1 weak (Kmet et al., 2004). The reached inter-rater reliability counted using Cohen's kappa was high at κ = 0.828 (Cohen, 1960;McHugh, 2012). The disagreements were resolved by discussion.

| Description of studies
All of the included papers, with one exception ( and the USA (Caldwell, 2010(Caldwell, , 2011. Information about the articles included in this systematic literature review is provided in Table 1, including quality assessment scores.

| Framework synthesis
The authors adopted a framework synthesis approach (Dixon-Woods, 2011), according to which the first stage is establishing a conceptual model a priori. The conceptual model-in this case the Dynamic Model of Wellbeing-provided a structure for data coding.  (2019), the present authors identified that some outcomes were complex to categorize, potentially falling under multiple "domains." Examples include "learning new skills" and "acquiring knowledge." While both of these outcomes connect to an increase in personal resources, they also relate to self-advocates' sense of competency (associated with good functioning and satisfaction of needs in the Dynamic Model).
In such incidences, the authors discussed and agreed upon a "primary" domain, while noting where it was important to draw attention to the interconnectedness of outcomes and their relationship with different domains.

| Coding
The

| FINDING S
The key findings are structured according to the domains of the Dynamic Model of Wellbeing, with additional issues unpacked during the data analysis.

| External conditions
According to NEF, the domain of external conditions includes the material, social and economic circumstances of a person's life, such as income, work, education, housing, social connections and living standards. In our review of the included papers, the present authors identified the following examples of how self-advocacy impacted upon people with intellectual disabilities' external conditions, for example: • New friendships and expanded social networks; • Opportunities for work (in paid or non-paid employment, volunteering); • Support to access information and resources (e.g. information about benefits, housing); • Support to make changes in external conditions (e.g. housing, relationships, work).
In relation to friendships and extended social networks, participants in Beart, Hardy, and Buchan's study (2004)

Key findings
Quality assessment Hall (2005) 21 people with intellectual disabilities and their supporters; age and gender not provided Scotland, UK Group interviews; a narrative approach To establish an account of various aspects of people's lives and the extent of their inclusion in particular sociospatial contexts Self-advocacy provided a space in which people felt respected, valued and connected. Self-advocacy was emerging as a site for collective action, but this was largely confined to awareness raising and improvements to services. While Hall acknowledges the significance of this, he argues that self-advocacy was limited in its possibilities for reimagining social inclusion at that point This is also supported by other studies included in this literature review (Caldwell, 2011;Frawley & Bigby, 2015;García Iriarte et al., 2014;Gilmartin & Slevin, 2009;Goodley et al., 2003). Mineur et al. (2017) in this context write about increased social capital, as people with intellectual disabilities engage in more social relationships (including online, via social media). Expanding people's social networks was also described as a key tool in relieving boredom (Anderson & Bigby, 2017, p. 115): "there's always something going on here. Outside, at home, there's nothing to do. It's really, really boring." In some studies (Beart et al., 2004;Frawley & Bigby, 2015), the participants mentioned that their self-advocacy organization provided them with supportive work opportunities. In addition, opportunities to sit on boards, reference groups and advisory committees, as well as to present at conferences and work on joint campaigns with other organizations, were provided by self-advocacy organizations (Frawley & Bigby, 2015;McNally, 2003), although one paper described these opportunities as "tenuous" (Caldwell, 2010 People involved with self-advocacy organizations also received (Anderson & Bigby, 2017;McNally, 2003) or anticipated receiving support from these organizations in making changes to the external conditions of their lives, such as housing. In some cases, the changes in external conditions came on smaller, yet still significant scale-such as having an opportunity to make a choice about one's breakfast (Anderson & Bigby, 2017

| Personal resources
According to the Dynamic Model of Wellbeing, personal resources are the attributes that individuals hold that have the capacity to support their well-being. In our reading of the literature, the present authors identified the following examples of self-advocacy's impact on individuals' personal resources: • Developing self-esteem and the confidence to speak up for oneself (and others); • Learning new skills; • Acquiring new knowledge; • Changes in self-concept.
A number of papers reported that participation in a self-advocacy group led to members gaining self-esteem and developing more confidence to speak up for themselves and others (Anderson & Bigby, 2017;Beart et al., 2004;Caldwell, 2011;Clarke et al., 2015;García Iriarte et al., 2014;Gilmartin & Slevin, 2009;McNally, 2003;Mineur et al., 2017). One self-advocate from Mineur et al.'s study (2017, p. 8) commented that joining a self-advocacy group resulted in "my self-esteem and my self-confidence (being) at its peak today." An increase in self-confidence resulted in people feeling more com- fortable to articulate what would make their lives better, as well as to complain about issues they were unhappy about. In some cases, the literature reported tangible improvements to people's daily lives as a result of people's increased self-esteem and confidence to challenge the status quo (Beart et al., 2004, p. 37). This was shown to enable people to take more control of their lives, providing a foundation for greater levels of automony, an outcome of the well-being domain "good functioning and satisfaction of needs" (Beart et al., 2004).
Increased levels of confidence could be also ascribed to a commonly experienced change of lifestyle, within a safe space (Anderson & Bigby, 2017).
Learning new skills through participation in self-advocacy was a common theme in the literature (Anderson & Bigby, 2017;Caldwell, 2011;McNally, 2003). People with intellectual disability learnt new skills in their self-advocacy organizations, such as decision-making (Gilmartin & Slevin, 2009;Mineur et al., 2017), making choices (McNally, 2003, skills for developing friendships (Anderson & Bigby, 2017), travel training and community safety (Anderson & Bigby, 2017), leadership skills (Caldwell, 2010) and research-related skills (García Iriarte et al., 2014), to name a few. This learning process was mutual and happened in a space of psychological safety (Clarke et al., 2015). Due to their involvement with a self-advocacy organization, they came across opportunities that they did not have before (e.g. speaking at conferences, taking part in training courses in order to develop self-determination and self-advocacy skills). This led to empowerment at an individual and collective level (Anderson & Bigby, 2017;Gilmartin & Slevin, 2009). Another skill set highlighted in the literature was that of "relational abilities," which entails developing greater empathy and understanding of others, and learning how to communicate more effectively with a wide range of people (Mineur et al., 2017). Another paper emphasized the importance of learning to say "no" when required (Clarke et al., 2015).
Self-advocacy also offers numerous opportunities for people to acquire new knowledge, either about oneself (Strnadová et al., 2018); other people (Clarke et al., 2015); or the social world (Chapman, 2004;Tideman & Svensson, 2015). Papers described how self-advocacy taught people about their rights (Gilmartin & Slevin, 2009), different service models (Clarke et al., 2015) and supported people to view previous stigmatizing incidences through a different theoretical and experiential lens (Beart et al., 2004;Caldwell, 2010). This latter point was crucial in helping to shift people's self-concept.
The present authors were struck by the number of papers that reported the ways in which self-advocacy had changed people's self-concept, otherwise described as "self-identity." Being part of a self-advocacy group appears to open up possibilities for multiple new positive self-identities, such as becoming an independent person (Anderson & Bigby, 2017), becoming a more respected person with status (Beart et al., 2004) and becoming more skilled and socially confident (Mineur et al., 2017). Some research indicated that through self-advocacy group membership some individuals came to view their intellectual disability as an aspect of their lives to be celebrated, rather than something to be ashamed of (Caldwell, 2010;Gilmartin & Slevin, 2009;Tideman & Svensson, 2015). In the main, the literature suggests that self-advocates are somewhat ambivalent regarding their explicit embracing of an "intellectually disabled" identity following engagement with a self-advocacy group.
However, some self-advocates did find new meanings in their previous experiences and began to imagine different and more positive futures for themselves as a result of participation in the group (Beart et al., 2004).
… they expressed a strong, bold social identity that challenged the core of notions about passivity and incapacity on the part of people with intellectual disability. For example, Trish from Green group defined a self-advocate as a person who can "just stand up and be counted, that's how I feel. I really can do that." (Anderson & Bigby, 2017, p. 115)

| Good functioning and satisfaction of needs
In the Dynamic Model of Wellbeing, the domain of good functioning and satisfaction of needs relates to four core outcomes: autonomy; competency; safety and security; and connectedness to others. The present authors reviewed the included papers to find examples of these outcomes, such as: • Self-advocates experiencing a sense of connectedness, particularly in terms of self-advocates positioning themselves within the wider intellectual disability community; • Self-advocates using their increased confidence and self-esteem to take control and fight for their rights; • Self-advocates acquiring competency through their involvement with the group; • Self-advocacy providing a safe psychology space for people to try new things and to experiment with different social identities.
Most of the reviewed articles described diverse ways in which being a part of a self-advocacy organization contributed to people's good functioning and satisfaction of needs. Self-advocates talked about how participation in the organization had widened their social networks and helped them develop new friendships, both with other people with intellectual disability and with people outside their self-advocacy organizations. This was critical in combating loneliness (Mineur et al., 2017;Power & Bartlett, 2018b) and led to gaining a sense of camaraderie via shared stories, jokes and memories of the group that developed over time (Anderson & Bigby, 2017;Clarke et al., 2015;Frawley & Bigby, 2015;García Iriarte et al., 2014;Goodley et al., 2003;McNally, 2003;Power & Bartlett, 2018b). In Strnadová et al.'s study (2018, p. 1,096), the participants reported that self-advocacy provides friendships, respect, being valued and cared for, with some comparing self-advocacy organizations to home: "I'm more happier here than home, actually" (Tamara).
Being members of a self-advocacy organization, and mentoring and supporting others, allowed people to develop a much deeper understanding of the shared experience of disability. This is described by one of the participants in Caldwell's study (2011, p. 320): That was one of my first national experiences. Just going to that meeting. … Just seeing all these people with disabilities. I guess that was one of the first times I realized that there are a lot of people in this world with disabilities and a lot of us have the same stuff in common. Tideman and Svensson (2015, p. 4) in this context write about self-advocates' shared experiences of "otherness," disability and safe space to be themselves without a threat of authorities intervening: When they met at the self-advocacy group, they could show themselves to be vulnerable, strong, or lost without it being seen as a matter for the authorities or others who traditionally wanted to sort out their lives for them.
While acknowledging interdependency, the participants across the studies were proud of becoming more independent and having more control over their lives (McNally, 2003).
As discussed previously, self-advocacy provides many opportunities for people with intellectual disabilities to increase their personal resources. This includes acquiring new knowledge, learning new skills and gaining the confidence to ask questions and challenge the status quo. This increase in personal resources often went hand in hand with individuals taking on a new role through self-advocacy, such as becoming a committee member or a chairperson. As demonstrated in this account, a sense of status often emerged through participation in self-advocacy, linked directly to the domain outcome of competency: I was a director. I was a director of a role play, about bullying.
Standing for your rights. I were very good. The present authors had about 70 people come (to a conference). To get our message across to social services and the police. To make things better for people with learning disabilities (Beart et al., 2004, p. 95).
In Hall's paper (2005, p. 112), Peter, a man with intellectual disabilities, talks about supporting others in order to "help them to get the best for themselves." This speaks to self-advocacy's role in enabling people with intellectual disabilities to acquire experience, expertise and credibility. This in turn gives self-advocates a platform to provide support to others. Providing support to others is not only an indicator of competency, but also implies the self-advocate has value and purpose through their role. In addition, supporting others serves to increase people's sense of connection to the wider intellectual disability and self-advocacy community, reinforcing a sense of connectedness.
Exemplifying the dynamic nature of well-being, as self-advocates became valued for their expertise and competency, they experienced not only an increase in self-confidence, but a change in social identity, leading to a virtuous cycle that served to increase well-being (Anderson & Bigby, 2017).
Evidence of competency is also cited in reports of self-advocates being connected to a social cause and affecting social change.
In a number of papers, self-advocates described the ways in which they believed self-advocacy was a platform for social change, and gave them opportunities to influence policy, shift attitudes and help make tangible changes to people's day-to-day lives (Gilmartin & Slevin, 2009).
All of this happens within a space in which self-advocates can ask questions and voice opinions, and where they can learn to say "no." Self-advocacy provides the safety and security required for people to take risks and make mistakes. These opportunities for personal development and richer social experiences led to a more positive sense of self which can counter stigma (Clarke et al., 2015).
Efforts to help others demonstrated across a number of studies highlighted the importance of collective action to improve an individual's functioning, as mentioned by one of the self-advocates in Beart et al.'s study (2004, p. 97): "It would be suicidal if the present authors did things on our own. The present authors need support from a self advocacy group… and there should be other self advocacy groups around to give support." There was a sense of collective dimension of self-determination, as people with intellectual disabilities in studies included in this systematic review worked not only towards their own, but also the collective well-being for the group (Mineur et al., 2017). Strnadová et al. (2018) also acknowledged that self-advocacy provided peer support and opportunities for teamwork, both supporting a sense of connectedness.

| Good feelings day-to-day and overall
The present authors acknowledge that studies included in this systematic literature review were not attempting to measure or report on people's happiness. Nevertheless, a number of studies did discuss people's feelings of happiness, joy and satisfaction linked to self-advocacy.
People involved in self-advocacy organizations felt happy to be self-advocates (Anderson & Bigby, 2017). They felt respected and valued (Strnadová et al., 2018, p. 1,096), as expressed by one of the self-advocates: …since I've come into this group I've been part of the group, I feel loved and cared for and everyone here is so nice and caring and friendly, and they're always here for me, so I'm glad I'm here with you guys.
Self-advocacy organisations also relieved people with intellectual disability from boredom (Anderson & Bigby, 2017). The participants expressed being happy that they were doing things that matter. It mattered to them that they were helping other people (Anderson & Bigby, 2017;Frawley & Bigby, 2015). Some people talked about feeling good about themselves and realising their own potential through self-advocacy (McNally, 2003). Some experienced a personal transformation as a result of their participation in self-advocacy: Gosh, it really gave me a new way to think about myself. I love myself. I am not saying I am perfect.
Nobody is perfect. I really like the person I see in the mirror. I hope to convey that to other self-advocates.
They can be great too . . . It really did change my life. (Caldwell, 2010(Caldwell, , p. 1008 These studies demonstrate that participation in self-advocacy organizations did support increased feelings of happiness, joy and satisfaction amongst some people with intellectual disabilities.

| Other important considerations
In addition to identifying a number of themes across the papers that mapped directly onto the Dynamic Model of Wellbeing, the present authors also observed that the theme of bullying, oppression and victimization emerged in many of the papers the present authors reviewed (Caldwell, 2010;Clarke et al., 2015;García Iriarte et al., 2014;Goodley et al., 2003;Power & Bartlett, 2018a;Strnadová et al., 2018). While the present authors did not identify papers suggesting that self-advocacy had reduced people's experiences of bullying or victimization, it was clear that self-advocacy sometimes provided a space in which these disturbing and traumatic experiences could be discussed and reflected upon. Sometimes self-advocates were able to re-frame these incidences through their self-advocacy group, enabling them to view their personal experiences as part of a wider system of oppression against people with intellectual disabilities. While the literature highlighted that bullying and abuse have been a feature of many self-advocates' lives, participation in a self-advocacy organization appeared to give some people new tools to manage past trauma more effectively and to take steps to protect themselves in the future. A number of studies (Anderson & Bigby, 2017;Clarke et al., 2015;Frawley & Bigby, 2015;García Iriarte et al., 2014;Goodley et al., 2003;McNally, 2003;Power & Bartlett, 2018b;Strnadová et al., 2018) demonstrated how self-advocacy can impact upon good functioning and satisfaction of needs. Improved personal resources provide the basis for more automony. The safe space of self-advocacy can provide an environment in which people share previous experiences of abuse and bullying, re-framing these events through a more political and structural lens. Self-advocacy may provide tangible opportunities for people to develop and showcase competency. But perhaps most strikingly, the studies the present authors reviewed suggested that self-advocacy offers powerful mechanisms for connectedness.

| D ISCUSS I ON
Some individuals reported the result of such connectedness as quite transformational.
The studies highlight the relationship between social interaction and self-development that can occur through self-advocacy. There is evidence that self-advocacy can provide an environment and a context to build meaning; learn about other people's lives; acknowledge the resilience of people with intellectual disabilities; develop inter-personal relationships; develop identity; and explore new roles.
It can also be a space in which to try out "new ways of being" (Clarke et al., 2015, p. 242). Studies show that self-advocacy can also be the basis for "subtle radicalism," both supporting individual change and social activism (Anderson & Bigby, 2017).
It is important to note that some studies touched briefly upon what might be described as the potential negative impacts associated with participation in a self-advocacy group, which may serve to reduce a person's well-being. For example, Beart et al. (2004) discussed the riskiness for some people of getting involved in self-advocacy, particularly in relation to managing other people's concern or distrust of the group ( level of responsibility within the group, and the model of self-advocacy organization in operation. This is an area of study that warrants further research. However, despite the potential negative impacts associated with self-advocacy in relation to well-being, our systematic review provides evidence that for many people these appear to be outweighed by the positive impact on well-being as a result of participation in a self-advocacy organization. The strengths of the papers reviewed here are that they highlight the ways individuals across groups in different countries have experienced self-advocacy over several decades. While our review focused on research that includes the direct contributions of people with intellectual disabilities (in order to capture data on subjective well-being), the present authors are mindful that this raises further issues for consideration. For example, is possible that one consequence of a review based on self-report alone is an overstatement of the positive aspects of self-advocacy, and a failure to consider its weaknesses. Redley and Weinberg's (2007) paper, not included in this systematic review because it related to a study of a UK Learning Disability Parliament, pointed to a tendency amongst academic studies of self-advocacy to favour liberal models of citizenship which prioritize voice over care, security and well-being. Furthermore, as Walmsley and Downer pointed out in 1997, few self-advocates have severe and profound learning disabilities-which would preclude their responding to the verbally based research methods exclusively relied upon for the papers reviewed here. The present authors found no evidence as to whether membership of a self-advocacy group supports the well-being of such individuals-indeed, they are largely absent in the literature on self-advocacy. One might add that there is an extensive grey or non-peer-reviewed literature on self-advocacy, which, for practical reasons, was excluded from the systematic review, but which might possibly shed different light.
As part of an inclusive process, the findings from this systematic review were discussed with the fifth author who has intellectual disabilities. She reported that her own experiences of being a member and an employee of a self-advocacy organization for over 20 years aligned with the conclusions of the systematic review that being a member of a self-advocacy group has a positive impact on one's well-being. She also highlighted the critical issue of someone's agency to be able to engage with a self-advocacy group. She remarked that "If people don't want support, then you can't help them. And it's their choice." As demonstrated in the review, self-advocacy can positively influence well-being, yet is not always accessible for those in a need of more substantial support.
Last but not least, she reflected that she was surprised that within the 16 articles reviewed, there had not been more discussion about what the self-advocacy groups "stand for, what is their mission and what are their objectives." As an example, she talked about her self-advocacy organization, which is grounded in person-centredness; that is, a person with intellectual disability and their needs and priorities are at the centre of their work. She acknowledged that other self-advocacy organizations take a different approach, and rather than supporting individual self-advocates in their goals, they instead focus is on a particular issue, for example rights of people with intellectual disabilities to be parents. She suggested that future research should examine the relationship between the model of self-advocacy organization in operation, and its impact of people's well-being.

| CON CLUS ION
This systematic review has shown that participation in self-advocacy organizations does appear to have significant impacts on the subjective well-being of people with intellectual disabilities across the four domains of the Dynamic Model of Wellbeing. In addition, self-advocacy groups can provide a space for people to discuss and re-theorize painful experiences of bullying and abuse. The present authors have highlighted both the strengths and limitations of the literature reviewed, notably its reliance on self-reporting. More research is needed to explore the potential impact of self-advocacy on people with profound intellectual disabilities, and different methodological approaches are required to capture more diverse perspectives. The present authors also argue that research is needed to explore the relationship between different self-advocacy models and well-being, as well as self-advocacy's impact on people with intellectual disabilities' physical and mental health in the contemporary context. In the meantime, self-advocacy organizations, statutory authorities, commissioners and other funding bodies should be made aware of the positive impacts of self-advocacy people's well-being as reported in the literature.