1.1 Data Sources and Eligibility

The following databases were searched for the period between January 1997 and December 2019: JSTOR, Science Direct, Scopus, Springer, SAGE, and Taylor & Francis. The databases were identified by the authors with the help from a librarian using a journal indexing system. The authors drew on the disability voting rights terminology to come up with operational search terms as indicated in Table 1.

The quality assessment of each article was based on the following criteria: reliability, accuracy, methods, relevance, and coherence.⁴ Following these criteria, a level of confidence was attributed to each article, ranging from “high confidence” if authors reported details for all the criteria, “moderate confidence” when findings corresponded to some of the criteria, and “low confidence” if the authors did not report most of the noted criteria. It is important to clarify that articles ranked as “low confidence” did not correspond to inadequate methods in collecting data, but rather a lack of a clear description of the methods used by the authors.

Other sources of literature to enhance comprehensiveness of the search and capture all relevant information included grey literature sources⁵ and Wikipedia Corpus. The critical appraisal of the grey literature followed the AACODS checklist (Authority, Accuracy, Coverage, Objectivity, Date, Significance) proposed by Jess Tyndall (n.d.). Eligible articles were peer-reviewed studies and grey literature published in English or with available English translations. Literature had a primary focus on defining, exploring or describing the research concepts: “political participation,” “barriers to political participation,” “electoral-assistive devices,” and “electoral practices.” Articles were both theoretical and empirical literature, targeting the general population and only randomly including individuals with specific impairments or conditions, from any country, and using both qualitative and quantitative study designs. Criteria for exclusion of articles were the following two: (i) findings or content not related to the objectives of the review or insufficiently informative results and (ii) editorial reviews.

1.2 Study Appraisal and Synthesis

The authors undertook a three-part article screening process. In the first stage, article titles were reviewed. In the second stage of article selection, the researchers reviewed titles and abstracts using the inclusion and exclusion criteria described above. Lastly, in the third stage, the researcher screened the full-text articles to determine if they met the inclusion/exclusion criteria. A sample of articles was double checked by another researcher from the project Democratic Governance by the Peace and the Human Rights: Multidisciplinary Approaches in Digital Environments (La Gran Colombia University) to confirm compliance with eligibility criteria of the scoping review. Key information about articles was extracted using a framework specifically designed for this review. The extraction included standard bibliometric information and details of the study.

2.1 Search Results

From 1,706 records identified through database searching, the author reviewed 103 full articles and retained 57 for this scoping review (see Graph 1). Of the (n=57) sources for final review, most publications, 74% (n=42) of the articles from academic journals included in the critical appraisal were attributed moderate confidence using the criteria described earlier. “Low confidence” was granted to the remaining 36.8% (n=15) of those documents whose authors did not provide sufficient information regarding the methods used to collect the data. Mostly, this review included documents written in English and published from 1997 to the recent works in 2019 (Graph 2).

Source: Adapted from Moher, Liberati, Tetzlaff &, Altman (2009).

Graph 1 Scoping Review Flow Diagram. 

Source: Own elaboration.

Graph 2 Period covered in the literature review. 

Based on the period covered in this review, the year 2006 constitutes a “breaking point” in the state of academic studies on the right to vote by persons with disabilities. This year corresponds to the signature of the UN CRPD. Year 2006 is, presumably, the “cut-off point” from which most academics initiated researching on countries’ efforts to improve the political participation in private and public lives of persons with disabilities. Similarly, the year 2014 is relevant in the work by disability researchers. No relevant historical data can be attributed to this fact.

In terms of the geographical coverage, the documents included were divided into seven groups regarding the countries or regions to which findings were attributed by the authors (Graph 3). There is a slight difference between the number of studies from Europe (18 in total) and those from the United States (22 in total). Interestingly, it was possible to trace articles published in academic journals from Africa, Australia, Canada, and Asia. For the latter region, documents correspond to countries such as India and Japan. These articles are mostly concerned with assistive technology products. Searching and screening were undertaken in October and November of 2019 (Graph 4).

Source: Own elaboration.

Graph 3 Geographical coverage of the literature review. 

Source: Own elaboration.

Graph 4 Summary of State-of-the-art Framework. 

2.2 Approaches to Political Participation of Persons with Disabilities

Political participation includes a wide range of activities through which people with disabilities express their opinions on the world and how it is governed. ^{Aseka-Oluchina (2015)} and ^{Schur & Kruse (2000)} note that political participation of persons with disabilities includes participation in elections through voting or having voted, holding offices at any branch of the government, joining and forming unions or political parties, participation in policy, and decision-making processes. ^{Schur, Meera & Ameri (2015)} add other activities to the list, including contacting elected officials, contributing money to campaigns and attending political meetings.

The existing literature extensively explores political participation within the realm of «citizenship». In their studies, ^{Meekosha & Dowse (1997)}, ^{Morris (2005)}, and ^{Lister (2007)} affirm that there is an absence of voices of persons with disabilities in contemporary citizenship literature and that disability is an essential element in understanding political struggles around citizenship. Therefore, a good starting point in examining the intricacies of political participation of persons with disabilities is the concept of citizenship.

This concept is clearly outlined by ^{Rankin (2009)}, where she develops the three parts or elements of Marshall’s concept of citizenship, namely the civil, the political, and the social. The civil element consists of the rights necessary for individual freedom, such as the liberty of the person, the right to own property and the right to justice. The political element of citizenship corresponds to the right to participate in the exercise of political power. Lastly, the social element of citizenship includes a wide spectrum of rights, such as economic welfare, security, and the right to live in society according to the standards prevailing in the society. In her studies on disability, ^{Morris (2005)} also follows Marshall’s concepts of civil, political and social rights. Morris highlights three dimensions of citizenship promoted by disability advocates: self-determination (seen as the capacity for free choice and the exercise of autonomy), participation (including political and community participation), and contribution (how citizens with disabilities contribute to economic and social life). Similarly, Lister has identified four values of inclusive citizenship that emerge from the standpoint of the excluded, particularly persons with disabilities: justice, recognition, self-determination, and solidarity (^{Lister, 2007}).

In recent studies, ^{Hvinden et al. (2017)}, explain the concept of “active citizenship” of persons with disabilities from three dimensions: a sense of security by making effective use of social rights, autonomy to define one’s needs, and influence through participation in public and private life. The contributions by ^{Morris (2005)}, ^{Lister (2007)} and ^{Hvinden et al. (2017)}, have as a common element the recognition of the “agency” of citizens with disabilities. In this context, it is possible to argue that public policies aimed at promoting political participation should set as a goal the furtherance of the ability to act of persons with disabilities, allowing them to participate in and be in charge of their own lives through the three elements of citizenship as envisaged by ^{Marshall (1950)}.

As shown, various authors have explored disability as an important field for the theoretical development of the concept of citizenship from a more “universalist” perspective. Furthermore, those authors have framed “citizenship” as a legal concept at the core of a true democracy. This is most clearly set out by inter alia^{Beckman (2009)}, ^{Agran & Hughes (2013)}, ^{Lawn et al. (2014)} and ^{Kopel (2017)}, where they note that active citizenship of persons with disabilities and the right to participate in political and public life are a fundamental part of functioning democratic states.

In the same vein, ^{IFES & NDI (2014)} note that the inclusion of persons with disabilities is fundamental to a true democracy. ^{Lister (2007)}, who argues that in democracies the citizenship struggles are articulated in terms of the tension between citizenship’s inclusionary and exclusionary sides, has made similar considerations. Furthermore, ^{Morris (2005)} also notes that building true democracies is a process embedded in an active/passive citizen debate.

Clearly, there is a tension inherent to the concept of citizenship. In schools, according to ^{Morris (2005)}, the aim is to produce “active citizens” who will vote, be involved in their local communities, and feel responsible for their societies. In these contexts, being an “active citizen” is equivalent to being a “good citizen.” The “active citizenship” is characterized for calling on members of a group to fulfil their responsibilities in addition to making claims regarding their rights, as noted by ^{Meekosha & Dowse (1997)}.

Persons with disabilities seem not to belong to the realm of “active citizenship.” Moreover, authors suggest how political initiatives to encourage “active citizenship” tend not to treat persons with disabilities as potential “active citizens” (^{Lister, 2007}; ^{Morris, 2005}). Particularly interesting is ^{Lord, Ashley & Fiala-Butora’s (2014)} analysis of how public imagination conceives most people with disabilities as passive citizens, helpless individuals as opposed to empowered citizens. Owing to the fact that “passive citizens” are seen as undermining democracies, ^{Meekosha & Dowse (1997)} note that persons with disabilities ended up being segregated to the realm of passivity and lack of agency. Excluded, persons with disabilities are denied the “opportunity” of being an “active citizen” and exercising their political rights.

The exclusion of persons with disabilities is furthered either by law, with physical obstacles hampering the exercise of an active role in democratic societies, or indirectly by discriminatory practices. The method how all forms of exclusion are embedded in a paternalistic/protective approach is depicted by inter alia^{Fiala-Butora, Ashely & Lord (2014)}, ^{Barclay (2013)}, ^{Combrinck (2014)}, ^{Kopel (2017)}, and ^{Ryan, Henderson & Bonython (2016)}. These authors explore how the concept of “capacity” for citizenship is influenced by medical discourse, and why testing persons with disabilities as having or not having a “capacity to vote” is discriminatory and violates the requirement of equality expressed in general international human rights law.

Generally, despite enfranchisement guarantees contained in international and regional human rights treaties, various authors affirm that persons with disabilities remain politically marginalized. As noted by inter alia^{Schur (1998)}, ^{Fiala-Butora, Ashely & Lord (2014)}, ^{Lord, Ashley & Fiala-Butora (2014)}, ^{Appelbaum (2000)}, ^{Atkinson, Aaberg & Darn (2017)}, ^{Ryan, Henderson & Bonython (2016)}, ^{Van Hees, Boeije & De Putter (2019)}, and ^{IFES & NDI (2014)}, persons with disabilities around the world face statutory and procedural barriers to political participation, specifically to voting.

^{Sackey (2014)} notes that since the return to democratic rule in Ghana in 1992, it was only until year 2013 that a minister with a disability was appointed in that country, and that afterwards neither had a single person with a disability been appointed as minister of state nor as a district chief executive in Ghana. This provides an example of the marginalisation status in the private and public lives of persons with disabilities. Similar findings were reported by ^{Schur and Adya (2015)}. These authors analysed disability measures in voting processes in the United States from the year 2006 to 2010 and found that citizens with disabilities remain less likely to vote than nondisabled citizens. Non-inclusive political scenarios are common to various countries and evidence suggests that citizens with disabilities are not yet equal participants in the political systems around the world.

Some scholars take note of how the exercise of political rights depends on equal access to political information and political activities. ^{Grobelaar, Mgijima & Njau (2018)}, ^{Fiala-Butora, Ashely & Lord (2014)}, and ^{Morris (2005)} suggest that political inequality is not due to disability per se, but to economic and social inequalities associated with disability. This is clearly outlined by ^{Priestley et al. (2016)}, where the authors note that disability equality should be considered along with other socio-economic variables when researching political participation. In the case of disability, as expressed by ^{Priestley et al. (2016)}, equality raises unique factors such as the legal denial of voting rights on grounds of mental capacity, the accessibility of the political process, and the political activism of the social movement by persons with disabilities.

^{Schur, Meera & Ameri (2015)}, following the model proposed by ^{Brady, Verba & Lehman (1995)}, also classify other factors that contribute to lower turnout among people with disabilities into three categories: resources, recruitment, and psychological. Resources, according to Schur, Meera & Ameri (2015), consist of level of education, time, money, and civic skills. Limited resources may affect voter turnout in a number of ways. For example, ^{Sackey (2014)}, when commenting on the work done by ^{Hillygus (2005)}, provides evidence of how participation in politics depends on the level of education. Sackey (2014) argues that education provides both the skills necessary to become politically engaged and the knowledge to understand democratic principles.

The recruitment process, as envisaged by ^{Schur, Meera & Ameri (2015)}, is conducted through formal and informal networks to which citizens belong. In the case of persons with disabilities, political recruitment is limited by their relative isolation. ^{Kelley (2010)} also attaches some importance to the community and social involvement as influencing political participation.

Finally, the psychological factors include political interest, civic values, and feelings of efficacy. As explained by ^{Schur, Meera & Ameri (2015)}, evidence indicates that people with disabilities discuss politics less frequently than citizens without disabilities. In this regard, ^{Ward, Baker & Moon (2009)}, ^{Lawn et al. (2014)}, and ^{Agran & Hughes (2013)} illustrate that interest in politics is reduced by stigma and discrimination associated with disability.

Many publications also focus on the right to a secret and independent ballot as an integral part of the fundamental right of persons with disabilities to vote. ^{Kanter & Russo (2006)} note that persons with disabilities often do not have the option of voting secretly and independently in a polling place. In this regard, ^{Mercurio (2003)} argues that the secret ballot reflects the democratic political instinct that political participation is an inalienable birth right that must be exercised as an act of individual free expression. Moreover, ^{Shaw (2006}, January 26) notes that the secret ballot offers protection from undue influence on voters. ^{Shulman (2010)} and ^{Gad & Dalsgaard (2017)} further elaborate the secrecy of the vote as one of the criteria which political scientists base their diagnosis of the democratic status of nation-states.

The secrecy of the vote is a crucial element for most democracies. Authors have briefly elaborated on accessibility, inclusive and universal design as prerequisites to enable persons with disabilities to enjoy their right to vote secretly and independently. In the existing literature, even less developed is the idea of how to secure a method of casting a secret and verifiable vote for persons with disabilities using assistive technology.

2.3 Barriers to Political Participation

The bulk of the academic literature concerns barriers faced by persons with disabilities which hinder their political rights. As noted by ^{IFES & NDI (2014)}, some barriers are unique to specific regions and stages of the electoral cycle. ^{Van Hees, Boeije & De Putter (2019)}, and ^{Fiala-Butora, Ashely & Lord (2014)} coincide in identifying two groups of barriers to political participation of persons with disabilities that are repeatedly found in various studies, namely statutory and procedural barriers to voting.

Research on prevailing guardianship laws and policies that bar persons with disabilities from exercising their franchise de jure is available from at least the 1990s, and it is interesting to note how many of the findings are still relevant in the contemporary disability context. Discriminatory electoral legal frameworks and regulations that restrict the legal capacity and autonomy of persons with intellectual disabilities have been extensively explored by inter alia Lord, Ashley & ^{Fiala-Butora (2014)}; ^{Grobelaar, Mgijima & Njau (2018)}; ^{Priestley et al. (2016)}; ^{Ward, Baker & Moon (2009)}; ^{Atkinson, Aaberg & Darn (2017)}; ^{Appelbaum (2000)}; and the ^{FRA (2019)}. These authors have analysed legal provisions that exclude persons with intellectual disabilities based on the idea that they lack the very personal attribute protected by the right to vote, which is the ability to exercise self-determination regarding the laws and individuals that govern society. These studies coincide in arguing that laws precluding persons with disabilities from voting contravene the CRPD and other regional human rights treaties, mainly the European Convention on Human Rights.

The existing literature also explores the procedural barriers to voting. ^{Kanter & Russo (2006)}; ^{Bell, McKay & Phillips (2001)}; ^{Schur & Meera (2012)}; ^{Combrinck (2014)}; and IFES & NDI (2014) inter alia note that voters with disabilities encounter inaccessible polling places, lack of assistive devices, inaccessible vote recording technologies, and disabled-based voting restrictions. In this context, ^{Atkinson, Aaberg & Darn (2017)}, and ^{Wass et al. (2017)}, also note that communication barriers limit access to information, physical barriers prohibit access to buildings and attitudinal barriers, such as stereotypes or stigma, and limit the access of persons with disabilities to public life. Other barriers are poorly trained election officials, as noted by ^{Hoerner (2014)}, complicated ballots, greater social isolation, lower levels of education and income, and lower feelings of political efficacy, as explored by Schur & Meera (2012).

Particularly interesting is the analysis by ^{Atkinson, Aaberg & Darn (2017)}; ^{Thuo (2016)}; and ^{Hoerner (2014)} of the existing “informal” barriers. ^{Thuo (2016)} provides an example of this category, where he notes that in Kenya there is an “informal guardianship” created by the family, on whom persons with intellectual disabilities are dependent for support. Families make decisions on behalf of persons with disabilities. Examples of these decisions include restrictions of freedoms of movement and exclusion from birth registration when a child is born with a disability. As it has been analysed in the academic literature, for instance by Lord, Ashley & ^{Fiala-Butora (2014)}, without birth registration, it is difficult to obtain a national identity card, which is a prerequisite for the voter registration process.

Furthermore, the contributions by ^{Thuo (2016)}, ^{Meekosha & Shuttleworth (2009)} explore how these “informal” barriers have gender bias, owing to the fact that women with disabilities are less supported in participating in society and freely socializing in spaces outside their homes. Undoubtedly, female voters with disabilities face multiple forms of discrimination and barriers more frequently.

A briefly elaborated aspect of the existing literature is the barriers imposed at other levels, including the Electoral Management Bodies (EMBs) and attitudes by electoral officials and poll workers towards voters with disabilities on election days. On this regard, few authors, such as ^{Kelley (2010)} have framed the refusal and inappropriate assistance by electoral officials to persons with disabilities at the polling stations as a barrier that hinders their participation.

2.4 Approaches to Electoral Assistive Devices (Assistive Technology)

^{Takeaki et al. (2017}, 5-7 December) and ^{Kline & Ferri (2017)} note that persons with disabilities use assistive technology products to gain functional ability to perform tasks of their daily life independently. Surprisingly, much of the recent academic literature ignores this aspect when discussing issues related to the right to vote of persons with disabilities. Of the few publications which directly discuss the issue, ^{IFES & NDI (2014)}, ^{Aseka-Oluchina (2015)}, ^{Mercurio (2003)}, and ^{McGrew (2012)} refer to the lack of a unique system for the provision of assistive technology to persons with disabilities when voting and the lack of uniformity between national and local elections when dealing with “electoral assistive technology.”

Some authors briefly recognise how the CRPD places a great emphasis on both assistive devices and universally designed technology. ^{Kline & Ferri (2017)} note how the CRPD bestows upon nation-states’ political parties a range of duties related to the provision of accessible technology and the promotion of universally designed goods.

In the same vein, ^{Aseka-Oluchina (2015)} argues that there is an obligation resulting from CRPD for States Parties to adopt all appropriate measures to ensure the right of persons with disabilities to vote on an equal basis with others. Moreover, as envisaged by Aseka-Oluchina, this obligation includes the use of assistive devices and new technologies to enable persons with disabilities to stand and hold public offices. Similarly, ^{Mercurio (2003)} notes that because the range of computerized voting systems is wide, states might be able to afford the option that fits budgetary restrictions. Mercurio also highlights how the use of technological voting means, such as a computer terminal or similar with audio or voice recognition software, ensures the right to a secret ballot by persons with disabilities.

Particularly interesting are the studies on the federal Help America Vote Act (HAVA) of 2002 from the United States. HAVA requires each polling place to use ‘assistive voting machines’ that allow voters with disabilities to cast their ballots in privacy. As suggested by ^{Kanter (2006)}, ^{Shaw (2006}, January 26), and ^{Hoerner (2014)}, HAVA does not comprise a statement of acceptable minimum standards for accessibility, nor does it provide a system for revising the standards in accordance with evolving technology. Studies on common standards of accessibility in Europe were not found.

In sum, the academic literature recognises that political participation requires the provision of reasonable accommodation and adequate assistance, and that advances in technology enable not only persons with disabilities to vote but also all voters alike, as noted by ^{Shulman (2010)} and Innovation for the Blind (2017). Nevertheless, there is insufficient literature concerning the provision of technology -in terms of high or low cost- as a measure to be adopted by states to ensure that voters with disabilities can exercise their rights in practice. Furthermore, surprisingly, voters’ understandings and knowledge regarding electoral assistive devices have been underexplored.

2.5 Electoral Practices

Despite the lack of attention for defining the concept of “practices” in the academic literature, a perusal of this literature shows that authors are generally in agreement on what is to be understood by “practices” from the social practice theorists such as Pierre Bourdieu and Anthony Giddens. Most of the academic publications examined on ‘electoral practices’ share the same definitional elements of what constitutes “practices” (i.e., actors who are knowledgeable about most of their actions and rely on structures to act).

The nature of the “practices” is often the subject of analysis in the academic literature. In general, the distinction is made between promising practices or best practices and exclusionary practices. With promising practices, voters with disabilities are enabled to exercise their franchise. ^{Grobelaar, Mgijima & Njau (2018)}; ^{Schur & Meera (2012)}; ^{Atkinson, Aaberg & Darn (2017)}; and the ^{International Institute for Democracy and Electoral Assistance IDEA (2014)} explore practices for removing voting obstacles, including professionalism of EMBs, recruitment of persons with disabilities to serve as election observers, and increasing polling place accessibility. Other “good practices” include training of election officials in disability issues, voter education, and reasonable modifications to avoid disability discrimination in electoral procedures. In this regard, ^{Belt (2016)} briefly elaborates on the training issues for poll workers on new technology.

She frames this type of training as a “bottleneck” in the electoral systems. Likewise, ^{Priestley et al. (2016)}, also note other “promising practices,” such as the opportunity structures for DPOs involvement in public policy development. These authors also positively value the involvement of political parties in carrying accessible meetings to inform potential voters about electoral procedures. Similarly, ^{Aseka-Oluchina (2015)} notes that relevant actors in the electoral scenario are political parties, which should ensure active participation of persons with disabilities.

Exclusionary practices, on the other hand, presuppose that persons with disabilities are reduced to the category of “passive” or “invisible” actors within electoral systems. This is most clearly established by ^{Combrinck (2014)}, where he identifies national practices that range from total exclusion of persons with disabilities from political participation, through a case-by-case consideration to full participation.

Most of the exclusionary practices, as noted by ^{Lister (2007)}, arise from structural issues that influence representations of persons with disabilities. These practices are determined by each state, as noted by ^{Agran & Hughes (2013)}, and correspond to particular social and cultural realities. Similar statements are made by the European Economic and Social Committee, where it notes that exclusionary practices in Europe are based on long-standing customs and not expressly provided for by law (^{Pater, 2019}).

In the academic literature, the view that various subgroups of actors influence political participation of persons with disabilities is prevalent. Nevertheless, only a few authors have carefully researched this issue. For example, ^{Hoerner (2014)} and ^{Wass et al. (2017)}, note how voters with disabilities may be discouraged by interactions with poll workers and election officials who lack adequate knowledge to deal with disabilities or to offer assistance. ^{Belt (2016)} notes that actors within the electoral system, such as poll workers, experience discomfort when helping voters who use accessible technology. Furthermore, ^{Ward, Baker & Moon (2009)} argued that election officials play a role as facilitators or inhibitors of voting by persons with disabilities. Ward et al. also recognized that there are no available empirical data about perceptions and attitudes of polling and election officials towards voters with disabilities. Surprisingly, it seems to be underexplored how different actors serve a variety of functions in supporting or constraining the democratic process.