Disability and poverty : two related conditions . A review of the literature

The relationship between disability and poverty has been recognised in the literature since the 1990s. Empirical evidence supporting the existence of this relationship has increased in the last decade; however, there is still a lack of knowledge of how these two conditions interact and what the causal mechanisms that participate in the creation of this relationship are. This article aims to explore how the concepts of disability and poverty are related and it analyses the bidirectional relationship between these two conditions, how it is mediated by social exclusion and what empirical evidence supports this relationship around the world and in Latin America (LA).


Introduction
The aim of this article is to explore how the concepts of disability and poverty are related.Both concepts have evolved in the last decades, presenting multiple definitions and, depending on the perspective, different dimensions that play a role in the social construction of these two concepts.This article analyses the bidirectional relationship between disability and poverty, how it is mediated by social exclusion and what empirical evidence supports this relationship around the world and in Latin America (LA).
Three main models to define disability can be found in the literature.The first is the individual model, which defines disability as an individual problem, the result of an impairment that limits an individual's ability to participate in the labour market.Under this model, a person with disability does not fulfil the social standards, therefore he or she cannot work or be an active member of the society (1)(2)(3).The individual model is based on a needs-based approach which establishes that welfare providers (States, Church, charities) should provide social services to specific groups, those who are seen as not able to participate as active members of the society.
The second model developed to support an understanding of disability is the social one.This model assumes disability is socially constructed; it gives an active role to society in the creation of disability.Under this model, social changes should occur in order to guarantee the full participation of people with disabilities.Indeed, legislation and social policies on disability aim to guarantee equal access to basic opportunities and services and to reduce discrimination (4).The social model is based on a rights-based approach that considers that social policies should guarantee human rights to all members of a society (5).
The third model was proposed by the World Health Organization (WHO) in the International Classification of Functioning, Disability and Health (ICF) (6).The biopsychosocial model or ICF model understands disability as the result of an interaction between a health condition and social barriers.This model has been highly influential at international and national levels.Indeed, the Convention on the Rights of Persons with Disabilities (CRPD) is based on the ICF model; this convention is the first official document that forces signatory states to fulfil a number of objectives in order to include people with disabilities in their societies.Additionally, the ICF model has also influenced the way disability is measured.In this context, the Washington Group on Disability Statistics (WG) has developed a short set of questions based on the ICF.This set was designed to be included in censuses or large national surveys.
Countries in LA have responded to the requests made by the UN and the WHO.Indeed, two of the most influential documents in the region were the Standard Rules on the Equalization of Opportunities for People with Disabilities and the CRPD.Most LA countries reacted positively to the promulgation of these two documents.The legislation on this topic started to include a perspective of equalization of opportunities after 1993 and a human rights perspective after 2008 (7).
The definition of disability plays an important role in understanding how this condition interacts with poverty.Indeed, the currently widely accepted definition of disability recognises that social factors play a determinant role in the construction of disability.Different models to define disability exist in the literature, and since the ICF was published in 2001, most LA countries included this definition in their national legislation on disability.Currently disability is understood as the result of the interaction between a health condition and different social factors that act as a barrier in the social inclusion process of people with disabilities (6).
The relationship between disability and poverty became more apparent after the acceptance of the Millennium Development Goals (MDGs) in 2001.Identification of who the poor are and where they live became a priority for most developing countries.It has been recognised that the lack of explicit inclusion of these group in the MDGs and development strategies, including programmes to reduce poverty, is one important limitation in the fulfilment of objectives related to eradicate extreme poverty (8,9).Disability is not only related to poverty, but also to chronic poverty.The negative economic consequences of disability affect individuals and their families.Several factors interact in the intergenerational transmission of poverty.Some examples of those are ownership of land or housing, low levels of education and poorly paid work opportunities (10,11).In households with disabled members, other factors also play a significant role; for example, indirect cost and changes in family roles.This last factor is associated with family members being caregivers and the type of strategies households implement in order to overcome potential reductions in income.Usually, when an adult becomes disabled, children may take the role of caregivers or may leave school in order to work; in both cases, there is a reduction in human capital of household members and it directly reduces the strategies and options households have to escape poverty.People with disabilities are not a homogeneous group.Their needs vary according to the type and severity of their impairment, alongside personal and social characteristics which can also affect their levels of vulnerability.In fact, depending on the type of impairment, different barriers may limit access to basic opportunities and services, such as education, health and employment.As a result of this heterogeneity, policies and strategies aiming to prevent, mitigate or overcome poverty for people with disabilities cannot be the same.There is no a unique strategy that will reduce the risk of poverty; consequently, this group needs to be fully and explicitly included in all strategies aiming to reduce poverty in developing countries (12)(13)(14).
Mechanisms to include people with disabilities in the development agenda have moved from a needs-based approach to a human rights approach.People with disabilities were an invisible group, usually not included in development strategies.After the publication of the document on Disability, Poverty and Development by the Department for International Development (DFID) (15), the importance of this group increased.Additionally, states that signed the CRPD have the obligation to guarantee human rights, to reduce discrimination and to improve the life conditions of people with disabilities.
Despite the fact that the relationship between disability and poverty has gained recognition in the last decade (16)(17)(18), there is little effort to analyse the dynamics of this relationship in LA.The relatively small number of sources of data including questions on disability and poverty is one reason why research on this subject is limited.In the last 10 years, the number of national surveys and censuses that include questions on the topic has increased, but still there is no in-depth analysis of this relationship and the identification and analysis of causal relationships is limited by the absence of longitudinal data.
The next section in this article describes the relationship between disability and poverty, followed by a discussion on how social exclusion acts as a mediating mechanism between both conditions.The existing empirical evidence is then presented for developing countries and for LA countries.
In the final part of the article consideration is given as to how disability has been included in policy reduction and development strategies.

Disability and poverty: A vicious circle
The understanding of poverty and disability has changed in recent decades.Disability has moved from an individual to an ICF model, where social barriers play a fundamental role in the creation of disability (6).Additionally, the perspectives employed to understand poverty have shifted from a monetary or an income based approach to a multidimensional one, where aspects related to access to basic opportunities and services play a major role.Given these changes, the study of the relationship between disability and poverty has moved from an analysis of disability as a health shock that increases the risk of poverty or impoverishment of an individual to a more complex relationship, which is bidirectional and associated with social exclusion.
In the last 15 years, the number of studies aiming to describe the relationship between disability and poverty in low and middle income countries has increased (19).Nevertheless, the evidence is fragile and the lack of longitudinal data does not allow a proper analysis of how these two conditions interact.The World Bank (WB) published a review of the literature on this topic in 1999 (16).This report argued that around 15% to 20% of poor populations in developing countries are people with disabilities and that households with disabled members have a higher risk of poverty (16).In addition to this report, after the promulgation of the MDGs in 2001, the analysis of who the poor are and why they are poor has become a priority in the development research agenda.It has been recognised that disability increases the risk of poverty and poverty increases the risk of disability, and people with disabilities constitute a large percentage of the poorest of the poor (17,20).
Disability and poverty have a bidirectional relationship; meaning that disability is a cause and a consequence of poverty (Figure 1) (16,17,21).On the one hand, low levels of nutrition, limited access to preventive health care, low access to sanitation and clean water and violence are some factors that increase the risk of becoming chronically ill for poor populations.On the other hand, people with impairments face extra costs and barriers in their access to health care services, including rehabilitation and technical aids; they are socially excluded from education and employment and have to assume direct, indirect and opportunity costs, which negatively affect their income and consumption (13,16,17,19,22,23).This is not a universal circle that affects all poor or disabled individuals.However, people living in poverty and people with impairments face higher risks of becoming disabled and poor, respectively.

Figure 1. Disability and poverty vicious circle
The interaction between disability and poverty depends on individual and social-demographic characteristics.Indeed, aspects related to age, gender, impairment (type and severity), country and region of residence have a direct effect on how the risk of poverty and disability increases (or not).The level of human, social and economic development of a country influences the type and quality of opportunities and services available for all members of a society, including people with disabilities (24).Nevertheless, physical, social and attitudinal barriers reduce the access to services and opportunities of this group.In a general context, people with disabilities face social exclusion and higher levels of poverty, even in developed countries, where social programmes have been established in order to allow for the extra costs of disability (25)(26)(27).
The understanding and study of this relationship has been limited by the nature of available data.A large amount of anecdotal evidence exists on the topic; but difficulties developing a set of questions that enables identification of who is disabled, and the lack of longitudinal data in developing countries, including information on disability, have been two limitations on the analysis of the causal relationship between these two conditions.
When poverty is understood from a multidimensional perspective, aspects related to access to basic opportunities and services are a priority.In this context, levels of health and education, the types of available employment, opportunities for social and economic participation and social and political empowerment are essential to define who the poor are and why they are poor.As a consequence of the large number of risks of poverty people with disabilities face and the effects of disability on the levels of poverty of an individual or a family, indirect measures of poverty do not capture the severity of this situation.In fact, aspects related to reduction in the levels of human capital, costs of care and effects of social exclusion are not considered in unidimensional measures of poverty (28).

From disability to poverty
Usually, people with disabilities are socially and economically marginalized.In general, they and their families are considered the poorest of the poor and are excluded from basic opportunities and services related to health, education and employment (Figure 2).In developing and developed countries, this group faces higher risks of poverty and impoverishment; has higher rates of unemployment and underemployment and lower education levels.These aspects reduce their human capital and increase their risk of being chronically poor (17,18,29).In general, people with disabilities around the world share similar characteristics.They are considered the poorest of the poor, have lower levels of education, higher rates of unemployment and underemployment, have fewer savings and a reduced number of assets including housing and land (13,(16)(17)(18)(19)21,22,24,(30)(31)(32)(33)(34)(35)(36).

Stigma and discrimination
The negative effects of disability are assumed by individuals and their families.In developing countries, indirect, direct and opportunity costs of disability are usually assumed by the family.This is given by the limited number of social protection services designed to cover these costs and the important role of the family as a welfare institution (37).In addition, the average level of human capital of a household with disabled members is reduced because people with disabilities have lower levels of education and higher levels of unemployment, and, in most cases, a member of the family adopts the role of caregiver (23).
Disability affects individuals and their families, and can have a different impact on people.The characteristics of a person before becoming disabled determine to some extent how available social resources can be used.However, access to basic services and opportunities for people with disabilities is usually limited by attitudinal, physical and informational barriers.Those barriers have a direct impact on levels of education and health and types of job to which this group has access to.In most cases, schools, universities and other education institutions are not adapted to include people with diverse educational needs, this is one main reason why parents of children with a disability are less likely to take them to school (18).In addition, transportation services are usually not accessible for individuals with reduced mobility, buildings are not designed to include people with physical impairments, information is not available in braille and only a small number of people can communicate using sign language (18).All these barriers result in people with disabilities having less access to basic services and should be considered when the relationship between disability and poverty is analysed.
People with disabilities face a "handicap conversion" (38).Meaning that a person with a disability would not reach the same levels of wellbeing that a person without a disability, even when they have the same amount of resources.This handicap conversion is one cause of how disability increases the probability of poverty of individuals and households.People with different impairments have special needs that should be covered and in most cases these needs reduce the levels of available income of individuals and their families, creating a poverty trap.
The needs of people with disabilities are usually invisible in social policies that aim to reduce poverty and to increase access to basic services and to the labour market.Aspects associated with the existence of negative stereotypes related to the ability of people with disabilities to work, to actively participate in a society and to learn new things are some of the causes of the invisibility of this group in the public agenda (39).In most cases, people with disabilities are considered a group that deserves help and are excluded as active members of a society.All of this increases the risks of poverty and reduces the opportunities for a person to live the life they want.
In conclusion, disability increases the risk of becoming poor or impoverished.Exclusion from basic services such as education and health has a negative impact on the levels of individual human capital.Extra costs associated with disability are also a main source of risk, not only for individuals but also for their families.If a member of a poor household becomes disabled, the risk of impoverishment and chronic poverty increases and a family can fall into a poverty trap.All these elements play a fundamental role in how the existence of impairments increases the risk of poverty of a person and his/her family.

From poverty to disability
In general, poor individuals face higher risks of becoming chronically ill or impaired.They have low access to health care, high levels of under nourishment and usually work and live in unsafe environments, aspects that result in higher risk of illness and injury (40).Added to this situation, when a person suffers impairment and is excluded from health care services, the risk that an illness becomes a disability is higher.In this context, being poor increases the risk of illness and when a person is excluded from health care services it increases the risk of disability.
Poverty is defined as a deprivation of certain basic capabilities, which include avoiding premature mortality, being under nourished and being illiterate.In this context, a person considered poor by definition has limited access to food, education, health care, employment and is usually at risk of suffering an illness, injury or impairment (41).The sum of these factors can create a vicious circle where poor people have higher risk of illness, in the cases where they become ill, barriers of access to health care services increase their risk of chronic illness and, added to social exclusion processes, the risk of disability is higher.In addition to this mechanism, low levels of education and knowledge have negative consequences in the type and quality of information poor individuals have access to, increasing the risk that a preventable disease becomes a chronic condition or impairment.Aspects related to working and living in dangerous places and poor hygienic living conditions (low access to clean sources of water and improved sanitations services) also contribute (Figure 3) (17,21,29,30,34,39).In conclusion, individuals living in poverty face different risks that increase their probabilities of becoming ill, having an accident and impairment.Added to this, exclusion from access to preventive, curative and rehabilitation health care services are determinant factors in how impairments become disabilities.

Multiple disadvantages
The likelihood of poverty increases with different personal and social characteristics.Certain segments of the population, including women, elderly, minority ethnic groups and people living in rural and remote areas, are more vulnerable to poverty.Indeed, when two or more of these characteristics are combined the risk of poverty and exclusion is higher (11).
In the case of people with disabilities, it has been recognised that disabled women and disabled girls have lower levels of opportunity in education and employment.In some countries, they have a lower possibility of getting married and starting a family.In general, women with disabilities experience higher levels of physical and sexual violence and are most likely to be excluded from social participation and usually do not have a voice (42,43).
In conclusion, individual and social characteristics increase the probability of being poor.In the case of disability, it has been recognised that women with disabilities face higher levels of discrimination and oppression.They experience higher risks of being victims of physical and sexual violence and in some cases of premature death.

Social exclusion of disabled people
Social exclusion plays a significant and important role in the relationship between disability and poverty.Exclusion from access to education, to health care and to employment contributes to the creation of a vicious circle between disability and poverty.There is an inter-relationship between disability, exclusion and poverty, which becomes stronger in developing countries, where social protection systems do not provide enough cover to this population.As discussed in previous sections, people with disabilities face barriers in accessing basic services and opportunities, in addition, poor people face exclusion from health care services increasing the risk that an impairment becomes a disability (17,29,40).
Access to education and labour are crucial to how disability can be a cause of poverty.The age of individuals when they become disabled determines to some extent their access to education and labour markets (18).In cases where a person became disabled at birth, the probability that he or she has access to education is lower compared with non-disabled individuals.Additionally, if the person was of working age, access to labour markets and especially to formal jobs becomes a main limitation for social inclusion.Finally, if the person becomes disabled after working age, access to education or labour is not the major issue, but access to health and care services is.
Social exclusion is usually mentioned as one main factor that contributes in the vicious circle between disability and poverty.Nevertheless, empirical evidence analysing how social exclusion acts as a mechanism between disability and poverty is scarce (25,40,44,45).In addition, as it will be discussed in the next sections, social exclusion is not sufficiently described in the analysis of the relationship between disability and poverty.
In conclusion, social exclusion helps in the understanding of how the relationship between disability and poverty is created.This phenomenon is associated with low access to basic opportunities and social and political participation.Two of the main areas where people with disabilities are excluded are education and labour markets.Both have a direct impact in the level of poverty for people with disabilities and their families.Social exclusion is also related to social justice and how minority groups do not have the same opportunities and are discriminated against accessing basic services, affecting their levels of wellbeing and quality of life.

Empirical evidence in developing countries
In the last 15 years a large number of studies have analysed the relationship between disability and poverty.However, the evidence for developing countries continues to be scarce and only a few studies have included a multidimensional perspective of poverty in the analysis (24,35,46,47).
Two types of analysis can be found in the literature: studies describing the main characteristics of people with disabilities and their families and, studies analysing the levels of income and consumption of people with disabilities.The first type of study suggests that people with disabilities in developing countries share characteristics associated with low access to education, health care and labour markets.In general, people with disabilities have lower levels of education (31,48); higher extra costs in health care (49,50); low access to rehabilitation and medical services (18,49); high rates of unemployment (18,21,34,51,52); low levels of political and social participation (18); low access to basic sanitation services, including a clean source of water and sewerage (53,54) and they usually live in marginalized areas (55).
Studies analysing levels of income and consumption of people with disabilities and their families are inconclusive.Indeed, depending on the country and the existence or not of social assistance programmes for people with disabilities; the levels of income and consumption are higher or lower to those from the general population (18).Nevertheless, it has been recognised that indirect measures of poverty do not capture the real magnitude of deprivation of households and individuals with disability.Indeed, the extra costs associated with each type of impairment, the costs related to caring and the human capital loss in a household are not captured by these types of measures (28).Different studies have calculated the poverty gap for people with disabilities and it has been suggested that poverty lines for people with disabilities and their household should be higher in order to include the extra direct and indirect costs that this group faces (56)(57)(58)(59).Studies including a multidimensional measure of poverty have concluded that people with disabilities are deprived in more dimensions that people without disabilities (24).
In conclusion, people with disabilities around the world share similar characteristics.Those are related to low access to education and employment, higher health care costs, limited access to rehabilitation and medical services and low levels of social and political participation.In general, they are excluded from basic opportunities and services, an aspect that increases their levels of poverty and their risks of becoming chronically poor.Empirical evidence about the impact of disability on income and consumption levels of a household is inconclusive; these aspects can be related to the existence of extra costs, which are not captured by indirect measures of poverty.Studies analysing the effect of extra costs on the final income of individual and families have concluded that it is important and necessary to establish a higher poverty line for people with disabilities.

Empirical evidence in Latin America
Although information on disability is scarce in LA, some studies have described this group and produced findings that people with disabilities usually share similar characteristics between countries.Indeed, people with disabilities in LA are often poor, have low levels of education, live in marginalized regions, have low access to health care services and are unemployed or working but not earning a salary (60)(61)(62).
Although empirical evidence in this topic has grown in the last decade, a detailed analysis of the levels of poverty of people with disabilities in the region is still to be undertaken.Studies using data from different LA countries have been conducted in the last decade, all aimed at describing the situation of people with disabilities and their families, and for the first time in 2012, the ECLAC presented an analysis of the situation of people with disabilities and their families in the region.Similar conclusions can be drawn from all these studies, indeed, people with disabilities in the region have low levels of education, high levels of unemployment and low access to health care, especially rehabilitation services.They are more likely to be victims of physical violence and women with disabilities face double sources of discrimination (sexism, disability), aspects that result in even lower levels of access to education, health and employment.Empirical evidence also supports that people with disabilities have lower levels of social participation and high levels of discrimination and stigma (37,45,(63)(64)(65)(66)(67)(68)(69)(70).
In general, empirical evidence in LA suggests that the situation of people with disabilities is not different than in other developing regions.Indeed, levels of income and multidimensional poverty of this group are higher compared with non-disabled individuals (13,19,24).Although evidence relating to income and consumption poverty is inconclusive, further research is necessary in order to determine how the extra costs of disability affect the level of income of an individual or a household with disability.Only one study (24) using a multidimensional measure of poverty based on the Alkire-Foster methodology included data from LA, according to its results, people with disabilities have higher levels of deprivation associated with extra health care costs and employment.

Poverty reduction, development strategies and disability
Social protection systems have implemented poverty reduction strategies in order to reduce, mitigate or overcome poverty.In the case of disability, some developing countries have implemented social assistance programmes with the objective to provide a minimum level of income to households or individuals with disabilities (23,52,71,72).Although different poverty reduction strategies have been implemented in developing countries, people with disabilities are still not correctly included or recognised in these strategies.It is assumed that people with disabilities are a homogeneous group with the same needs and characteristics, therefore it is also assumed that strategies designed for vulnerable groups directly include people with disabilities (73).In addition, people with disabilities are a relatively invisible group in the development agenda.Usually, disability is considered a costly situation, in terms of human and economic resources and it is mostly associated only with health care, aspects that reduce its importance on the public agenda and is a cause of the invisibility of this situation (12).
The complex relationship between disability, labour, poverty and social assistance, in most cases, limits access to employment for people with disability.It has become a reason as to why some individuals with disabilities self-exclude themselves from labour markets and have low opportunities to participate actively in employment (23,52,71,74,75).
During the last five years, the recognition of the importance of including people with disabilities in development strategies has growth.Indeed, in the discussions for the post-2015 framework, people with disabilities are identified as a priority.As a result, policies and programmes to address the relationship between disability, social exclusion and poverty should be included as a priority in the national and the international development agendas (53,54,76).
After the introduction of the CRPD, signatory states committed to tackle discrimination and reduce barriers in access to health and education services, to decent employment and to social and political participation.These aspects should contribute in the reduction of the levels of poverty of people with disabilities and their families.(11)(12)(13)(14).In order to reduce the high levels of social exclusion faced by this group, development policies should also include strategies to reduce discrimination and to guarantee the human rights of this group.Moreover, there is a need to increase empirical evidence on the lives of people with disabilities; given the lack of rigorous and high quality research on this topic, the inclusion of disability in the development agenda has been limited (12).
In the case of LA, two types of social assistance programmes exist: Conditional Cash Transfers (CCTs) and non-contributory pensions.CCTs programmes do not usually explicitly consider people with disabilities as potential participants, becoming a major barrier for the participation of families with disabled members.Additionally, barriers faced by people with disabilities and their families become a factor that limits the fulfilment of the conditions that these programmes impose to their beneficiaries.Architectural and attitudinal barriers in health care and education services mean the cost of getting a grant are higher than the benefits obtained (71,77,78).
In conclusion, people with disabilities have often not been included in the development agenda.They are not usually explicitly mentioned in development strategies, or other documents aiming to reduce poverty and social exclusion.It has been recognised that the lack of inclusion of people with disabilities in development goals has negative consequences on the efficacy of the goals themselves.The no mention of this group on the MDGs has limited the effect of poverty reduction strategies on poor households with disabled members.Given the recognition of how important it is to include people with disabilities in poverty reduction strategies, the post-2015 framework has explicitly mentioned disability as a priority group.

Conclusions
In this paper it is considered that disability and poverty have a bidirectional relationship, meaning that both are cause and consequence of the other.In the case of poor individuals the risks of illness, injury or impairment increase as a result of living in unsanitary and dangerous conditions, low access to preventive and curative health care services and dangerous working conditions.The analysis presented from the literature shows that people with disabilities and their families face higher risks of poverty and impoverishment, because of their low access to education and employment; the extra cost of disability; the reduction in the levels of human capital of a household and the cost of care (indirect and opportunity costs).
Despite empirical evidence on this topic increasing in the last 15 years, most developing countries still need to conduct a detailed analysis of this relationship.In LA, some studies have analysed the socioeconomic characteristics of this group, but a detailed analysis of the relationship between disability and poverty in the region was not found.Only one study, using a multidimensional measurement of poverty, has included some LA countries, concluding that levels of deprivation and multidimensional poverty of people with disabilities are higher compared to individuals without disabilities.
Disability and poverty.A literature review: S113-23