Capability approach
The capability approach is a theoretical framework in welfare economics and political philosophy that evaluates human development and justice according to individuals' substantive freedoms—or capabilities—to achieve valued "functionings," such as being nourished, educated, or participating in community life, rather than relying solely on resource distribution, income levels, or reported happiness.[1] Primarily developed by Nobel laureate Amartya Sen starting in the late 1970s, it posits that true well-being arises from the conversion of commodities and personal endowments into real opportunities, influenced by factors like health heterogeneity, social norms, and environmental constraints, thereby challenging utilitarian and resourcist paradigms that overlook such variations.[2] Philosopher Martha Nussbaum advanced the approach in the 1990s by articulating a partial list of ten central capabilities, including bodily integrity, senses and imagination, and affiliation, as universal thresholds for human flourishing, with applications in feminist theory, human rights advocacy, and policy design.[1] While the framework has shaped tools like the United Nations' Human Development Index by incorporating non-income dimensions of progress, it has drawn criticism for operational ambiguities in identifying and measuring capabilities, potential paternalism in predefined lists, and limited empirical tractability compared to quantifiable metrics like GDP, despite some studies showing capabilities diverging from income correlates in poverty assessments.[3][4]History and Development
Amartya Sen's Early Contributions
Amartya Sen initiated the capability approach through his critique of dominant frameworks in welfare economics and egalitarian theory, which emphasized utility, income, or resources as metrics for well-being and justice. In his Tanner Lecture "Equality of What?", delivered at Stanford University on May 22, 1979, Sen argued that equalizing utilities fails due to interpersonal variations in pleasure derivation and adaptive preferences, as seen in cases of chronic deprivation where individuals adjust aspirations downward, such as during famines. He rejected resource-based equality, like Rawlsian primary goods, for ignoring "conversion" differences—personal, social, and environmental factors affecting how resources translate into actual opportunities, exemplified by a sighted person and a blind person receiving identical resources yet achieving disparate outcomes in mobility or nutrition. Sen proposed capabilities—the real opportunities individuals have to achieve valuable "functionings" (beings and doings, such as being nourished or participating in community life)—as the appropriate space for egalitarian concern, prioritizing substantive freedoms over mere endowments.[5] Building on this foundation, Sen's 1985 monograph Commodities and Capabilities, based on his 1982 Professor Dr. P. Hennipman Lectures at the University of Amsterdam, systematized the approach by distinguishing commodities (externally observable goods) from their characteristics, achieved functionings, and the capability sets representing alternative combinations of functionings. He contended that welfare assessments must evaluate not just commodity bundles but the capabilities they enable, accounting for diverse conversion processes influenced by individual heterogeneity (e.g., metabolism affecting nutritional needs) and contextual barriers (e.g., gender norms restricting women's access to education). This framework extended Sen's earlier social choice theory work, including his 1970 book Collective Choice and Social Welfare, by integrating ordinal interpersonal comparisons and avoiding utilitarian aggregation pitfalls.[6][7] These early formulations addressed limitations in GDP-centric development metrics, drawing from Sen's empirical studies on poverty and famine, such as his analysis of the 1974 Bangladesh famine where food availability was sufficient but entitlement failures curtailed capabilities. By 1985, Sen had established capabilities as a partial but essential criterion for justice, emphasizing evaluation over precise interpersonal comparisons of utility, while acknowledging incompleteness in ranking capability sets to preserve flexibility in pluralistic societies.[5][6]Martha Nussbaum's Refinements
Martha Nussbaum, collaborating initially with Amartya Sen, advanced the capability approach by developing a more specified framework oriented toward human dignity and justice, introducing a list of ten central human capabilities as thresholds that political institutions should secure for all citizens.[1] This refinement, first detailed in her 2000 book Women and Human Development, shifts from Sen's emphasis on comparative freedoms and agency toward a sufficientarian standard ensuring basic opportunities for functioning in line with human nature.[8] Nussbaum's version draws on Aristotelian ethics, Kantian respect for persons, and Rawlsian political liberalism, framing capabilities as entitlements derived from each person's inherent worth rather than purely consequentialist outcomes.[2] The ten central capabilities, intended as a partial but universal basis for evaluating justice across cultures, include: (1) life (mortality within normal spans); (2) bodily health (nutrition and shelter); (3) bodily integrity (movement, reproduction without assault); (4) senses, imagination, and thought (education, information access); (5) emotions (attachments without fear); (6) practical reason (planning one's life); (7) affiliation (sympathetic relationships, self-respect); (8) other species (nature interaction); (9) play (leisure); and (10) control over one's environment (political participation, property ownership).[9] [10] These are not exhaustive but serve as "core entitlements" with defined thresholds below which societies fail in justice, allowing for contextual adaptation while maintaining cross-cultural applicability.[11] Unlike Sen's open-ended evaluation, which prioritizes public reasoning to select relevant capabilities contextually, Nussbaum's approach mandates these ten as minimally essential, critiquing Sen's agnosticism on specifics as insufficient for institutional design and global policy, such as in human rights or development aid.[1] [12] She argues this list operationalizes the approach for constitutional guarantees, as in her proposals for international development where states must enable these capabilities up to adequacy levels, informed by empirical assessments of deprivation.[13] In Creating Capabilities (2011), Nussbaum further refines this by distinguishing internal capabilities (trained potentials) from combined ones (external opportunities), emphasizing state duties to remove barriers like discrimination.[11] This structured specification has influenced applications in gender justice and disability policy, though critics note its potential rigidity compared to Sen's flexibility.[2]Institutional Growth and Recent Advances
The Human Development and Capability Association (HDCA) was established in September 2004 during the Fourth International Conference on the Capability Approach in Pavia, Italy, marking a pivotal step in institutionalizing the framework through a dedicated global network of scholars and practitioners.[14] By 2025, the HDCA had expanded to over 800 members across more than 70 countries, fostering regional networks and 16 active thematic groups focused on areas such as work, employment, health, and education.[15] This growth facilitated annual international conferences, beginning with early capability-focused gatherings and continuing with events like the 2024 conference in Kolkata, India, on crises and capabilities, and the planned 2025 conference in Bradford, UK, emphasizing culture, peace, and capabilities.[16] The association also supports the quarterly Journal of Human Development and Capabilities, which disseminates peer-reviewed research on capability expansion across economic, social, political, and environmental domains.[17] Recent institutional advances include the launch of HDCA podcasts in the early 2020s to broaden accessibility and public engagement with capability concepts.[18] Thematically, the approach has seen deepened integration into policy-oriented applications, such as aligning with the United Nations Sustainable Development Goals (SDGs) by prioritizing substantive freedoms over resource metrics alone.[19] Specialized groups, like the Work and Employment Thematic Group formed in 2019, have driven targeted research, culminating in special journal issues examining capabilities in labor markets amid automation and inequality.[20] Advancements in the 2020s have extended the framework's empirical reach, with applications in housing design to enhance well-being through Sen- and Nussbaum-inspired valuations of future-oriented capabilities, as explored in 2025 studies.[21] Similarly, integrations with social work practices for disadvantaged children emphasize normative foundations for agency enhancement, while land policy analyses incorporate capabilities to address substantive freedoms in resource access.[22][23] These developments reflect a multidisciplinary maturation, evidenced by 2024 bibliometric analyses highlighting the approach's evolution from philosophical roots to interdisciplinary critiques of well-being metrics.[24]Core Theoretical Elements
Functionings and Capabilities Defined
In the capability approach, functionings refer to the actual achievements of individuals—the various beings and doings that a person values or has reason to value, such as being nourished, literate, or socially engaged.[25] These represent realized states or activities, contrasting with mere resource possession, as they account for what individuals effectively accomplish given their personal circumstances and choices./03:_Clarifications/3.02:_Refining_the_notions_of_capability_and_functioning) For instance, a functioning might include being healthy through adequate nutrition or participating in political processes, emphasizing outcomes over inputs like income or commodities.[26] Capabilities, by contrast, denote the substantive freedoms or real opportunities available to individuals to achieve those valuable functionings, comprising the alternative combinations of functionings feasible for a person to select.[25] Amartya Sen, who formalized these concepts in his 1985 work Commodities and Capabilities, distinguishes capabilities as abilities or potentialities rather than mere achievements, arguing that evaluating well-being solely through functionings overlooks individual agency and choice—for example, the freedom to fast despite nutritional capability.[27] This focus on capabilities prioritizes expansion of opportunities over guaranteed outcomes, as capabilities reflect what persons can do or become, influenced by personal, social, and environmental factors.[2] The distinction underscores the approach's emphasis on freedom as central to human development: functionings capture "what a person is" or "does," while capabilities represent the "ability to achieve" those states, enabling assessments of inequality based on opportunity sets rather than achieved levels alone.[28] Sen contends this framework avoids paternalism by respecting reasoned valuations of functionings, though it requires identifying valuable ones through public reasoning rather than fixed lists.[25] Martha Nussbaum builds on this by refining capabilities into types, such as basic (innate potentials), internal (developed through training), and combined (effective opportunities amid external conditions), to highlight barriers like discrimination in realizing functionings.[27]Agency, Conversion Factors, and Freedom
Agency in the capability approach denotes the ability of individuals to act purposefully in pursuit of goals they themselves value, distinct from passive receipt of well-being. This concept emphasizes autonomy and commitment, positioning agents as ends in themselves rather than mere instruments for external objectives. Amartya Sen introduced agency to highlight the process dimension of capability development, where individuals exercise reasoned choice amid constraints, thereby integrating ethical evaluation of actions with outcomes.[29] In Sen's framework, agency achievement is assessed by the extent to which persons can advance their commitments, even if these conflict with personal well-being, as seen in cases of sacrifice for family or community.[30] Conversion factors mediate the transformation of resources—such as income or commodities—into capabilities, determining the efficiency with which individuals achieve valued functionings. These factors operate at personal, social, and environmental levels: personal ones include physiological traits like metabolism or disabilities, which affect how resources yield nutrition or mobility; social factors involve institutional rules, gender norms, or public policies that enable or restrict access; environmental factors encompass climate, infrastructure, or geography influencing resource utility.[31] For instance, a wheelchair user's capability to achieve mobility from the same bicycle resource as an able-bodied person depends on personal conversion (physical capacity), social conversion (ramp availability), and environmental conversion (terrain flatness).[32] Variations in conversion factors explain why equal resource distribution does not yield equal capabilities, underscoring the approach's critique of resource-based metrics like GDP per capita.[33] Freedom constitutes the core of capabilities, defined as substantive opportunities—the real, effective alternatives individuals have to achieve functionings they value—rather than formal liberties decoupled from feasibility. Sen articulates this as "development as freedom," where expanding capabilities enhances both intrinsic well-being and instrumental agency, fostering processes like economic participation and political voice.[34] Substantive freedoms integrate agency by allowing agents to convert resources via personal and contextual factors into autonomous choices, while conversion factors themselves reflect freedoms' contingency on societal arrangements.[35] Thus, evaluating freedom requires assessing not just achieved functionings but the capability set's breadth, prioritizing removal of unfreedoms like illiteracy or discrimination that narrow conversion efficiency.[25]Normative Evaluation of Individual and Social Well-Being
The capability approach normatively grounds the evaluation of individual well-being in the substantive freedoms individuals have to achieve valuable functionings—defined as the beings and doings that constitute a life one has reason to value, such as being healthy or participating in community life.[1] Unlike utilitarian measures centered on subjective utility or satisfaction, which Sen critiques for accommodating adaptive preferences where deprived individuals lower their aspirations, capabilities emphasize effective opportunities adjusted for personal heterogeneities like disabilities or gender norms that affect resource conversion into achievements.[2] This focus on real freedoms avoids the paternalism of prescribing specific outcomes while rejecting resource-based metrics, such as income or Rawlsian primary goods, for ignoring how identical resources yield divergent capabilities across individuals due to varying conversion factors.[1] Agency plays a central role in this normative framework, extending well-being assessment beyond passive states to include the capacity for reflective choice and commitment to goals that may transcend personal advantage, such as advancing social justice.[1] Sen posits that individual advantage is multifaceted, encompassing not only well-being achievements but also agency achievements, where freedoms are evaluated holistically to capture human diversity and avoid reducing lives to hedonic aggregates or material endowments.[2] Nussbaum refines this by advocating thresholds of central capabilities as minimal requirements for a dignified life, normatively prioritizing protections against severe deprivations in domains like bodily integrity and practical reason over aggregate utility maximization.[1] For social well-being, the approach assesses arrangements by the capability sets they enable across a population, advocating comparisons that address interpersonal variations and distributional inequalities rather than simple aggregates of resources or happiness levels.[1] This entails evaluating institutions and policies for their role in expanding freedoms, including public goods like education systems that enhance conversion factors, while critiquing structures that systematically curtail opportunities, such as discriminatory laws limiting female mobility.[2] Normatively, social justice under the approach demands partial equality in capabilities—supplemented by democratic deliberation to resolve trade-offs—over egalitarian resource distribution, as the latter fails to account for causal influences on human flourishing like environmental barriers or social norms.[1] Collective capabilities, such as community-level freedoms to influence policy, further integrate social interdependence, recognizing that individual opportunities often depend on shared institutional designs.[1]Specified Frameworks
Nussbaum's Central Human Capabilities
Martha Nussbaum specified a list of ten central human capabilities in her 2000 book Women and Human Development: The Capabilities Approach, presenting them as essential thresholds for a minimally dignified human life that governments and international institutions should secure for all citizens. Unlike Amartya Sen's more abstract framework, Nussbaum's list provides concrete entitlements derived from philosophical inquiry into human nature, cross-cultural surveys of perceived necessities, and analysis of political constitutions worldwide, emphasizing capabilities over mere resources or utilities due to interpersonal variations in conversion factors such as disability or gender norms. She views these as partial in scope—focusing on political principles rather than comprehensive ethics—and subject to revision based on empirical evidence, while arguing that failure to achieve thresholds in any capability constitutes a grave injustice.[36][8] Nussbaum's capabilities are interrelated, with each requiring supportive social arrangements; for instance, education underpins sensory and imaginative development, while political participation demands bodily integrity. She thresholds them at levels informed by global data on life expectancy, nutrition standards from organizations like the World Health Organization, and legal protections in functioning democracies as of the late 1990s, such as average human lifespan exceeding 60-70 years in developed contexts versus premature mortality rates in impoverished regions documented by United Nations reports. Critics, including some economists, contend the list's philosophical foundations overlook quantifiable trade-offs, but Nussbaum counters that empirical metrics like infant mortality rates (e.g., 50+ per 1,000 births in sub-Saharan Africa circa 2000) validate prioritizing capabilities over aggregate income.[36][13] The ten central capabilities, as articulated by Nussbaum, are:- Life: Being able to live to the end of a human life of normal length, avoiding premature death or reduction of life to a state not worth living, supported by evidence from demographic studies showing correlations between access to sanitation and longevity gains of 20-30 years in industrialized nations post-1900.[36]
- Bodily health: Being able to maintain good health, including reproductive health, adequate nourishment, and shelter, reflecting data from the 1990s World Bank reports on malnutrition affecting 800 million people globally, which Nussbaum links to capability deprivations beyond resource scarcity.[36]
- Bodily integrity: Being able to move freely, secure against assault (including sexual and domestic violence), and exercise choice in reproduction and sexual satisfaction, drawing on UN statistics from 2000 indicating 1 in 3 women worldwide faced gender-based violence, which impairs agency irrespective of economic output.[36]
- Senses, imagination, and thought: Being able to use senses, imagine, think, and reason in a humanly developed way, cultivated by education (including literacy and basic sciences), protected by freedoms of expression and religious exercise, and free from non-beneficial pain, with Nussbaum citing literacy rates below 50% in parts of South Asia as barriers to innovation evident in patent data disparities.[36]
- Emotions: Being able to form attachments to people and things, experience love, grief, and justified anger without blighted development from fear or anxiety, necessitating social supports like family policies that, per 2000 OECD data, correlate with lower depression rates in supportive welfare states.[36]
- Practical reason: Being able to form conceptions of the good and critically reflect on life planning, safeguarded by liberties of conscience and religious observance, which Nussbaum ties to autonomy indices showing higher scores in societies with legal secularism post-Enlightenment reforms.[36]
- Affiliation: Comprising (a) living with concern for others, engaging in social interactions, and imagining others' situations, protected by assembly freedoms; and (b) having bases for self-respect and non-humiliation through equal dignity and anti-discrimination laws, informed by caste and race discrimination studies revealing productivity losses of up to 20% in unequal labor markets.[36]
- Other species: Being able to live in relation to animals, plants, and nature with concern, extending ethical consideration beyond humans based on ecological interdependence data, such as biodiversity loss impacting food security for 1 billion people by 2000 estimates.[36]
- Play: Being able to laugh, play, and enjoy recreational activities, which Nussbaum substantiates with psychological research on leisure's role in cognitive recovery, absent in child labor contexts affecting 250 million children globally per International Labour Organization figures from 2000.[36]
- Control over one's environment: Including (a) effective political participation with rights to speech and association; and (b) property rights, employment opportunities, and workplace dignity on equal terms, freedom from seizure, and mutual recognition in labor, aligned with Gini coefficient data showing inequality hampers mobility in low-participation regimes.[36]
Variations and Lists in Different Contexts
The capability approach accommodates variations in capability lists tailored to specific evaluative contexts, reflecting its emphasis on contextual relevance rather than a singular universal framework. While Martha Nussbaum advocates a partial list of central human capabilities applicable across societies, proponents like Amartya Sen and Ingrid Robeyns underscore the approach's flexibility, allowing lists to be adapted based on domain-specific priorities, such as poverty alleviation, gender equity, or sectoral policy. This modularity enables the identification of functionings and capabilities deemed valuable within particular social, cultural, or institutional settings, without prescribing exhaustive universality.[37] In multidimensional poverty measurement, Sabina Alkire and James Foster developed a framework grounded in the capability approach, operationalizing poverty through deprivations in weighted dimensions reflective of basic freedoms. Their Alkire-Foster method, implemented in the Global Multidimensional Poverty Index (MPI) since 2010, selects capabilities corresponding to health (nutrition and child mortality), education (years of schooling and attendance), and living standards (access to cooking fuel, sanitation, water, electricity, housing, and assets). These dimensions, chosen for their empirical tractability and alignment with valued functionings like sustenance and knowledge, have been applied in over 100 countries, identifying acute poverty affecting 1.3 billion people as of 2023 data from the Oxford Poverty and Human Development Initiative.[38] Contextual adaptations appear in gender justice analyses, where Robeyns proposes capability lists emphasizing relational and bodily dimensions often undervalued in resource-based metrics. For instance, capabilities for bodily integrity (freedom from violence and reproductive control) and affiliation (respect and non-discrimination) are prioritized to address gender-specific barriers, as evidenced in evaluations of policies in Europe and developing regions. In education, variations focus on capabilities for practical reason, imagination, and learning, extending Nussbaum's list to include domain-specific functionings like critical thinking and social participation, as applied in medical training reforms to enhance trainee agency beyond rote skills.[39][40] Health applications yield specialized lists, such as those integrating capabilities for bodily health, senses/imagination, and emotions, adapted to assess interventions like mental health promotion. A 2016 framework by Mitra et al. outlines health-related capabilities including mobility, pain avoidance, and psychological functioning, validated through cross-country studies showing superior explanatory power over income alone for well-being disparities. These variations maintain the approach's core normative focus on freedom while permitting empirical refinement, though debates persist on selection criteria to avoid subjective bias.[41][42]Operationalization and Measurement
Conceptual Hurdles in Quantifying Capabilities
One primary conceptual hurdle in quantifying capabilities arises from their inherent multidimensionality and the challenge of aggregation. Capabilities encompass a diverse array of freedoms across domains such as health, education, and social participation, which are often incommensurable, making it difficult to combine them into a coherent scalar measure without imposing arbitrary weights or losing nuanced information.[1] This issue is exacerbated by Amartya Sen's emphasis on capabilities as sets of potential functionings, where the value lies not just in individual elements but in the overall feasibility and choice within the set, complicating direct numerical representation.[4] A further difficulty stems from the distinction between achieved functionings—what individuals actually do and are—and capabilities as the underlying freedoms or opportunities to achieve those functionings. Measuring capabilities requires assessing counterfactual scenarios and hypothetical choices, which demand extensive data on personal, social, and environmental conversion factors that transform resources into real opportunities; however, these factors vary idiosyncratically and are empirically elusive, rendering precise quantification inherently approximate rather than exact.[3] Sen acknowledges this in his framework, noting that evaluating well-being via capabilities avoids the pitfalls of utility or resources but introduces high informational burdens for interpersonal comparisons.[1] Selection of relevant capabilities poses another barrier, as there is no universally agreed-upon list or criteria for inclusion, leading to debates between fixed enumerations, like Martha Nussbaum's ten central capabilities, and Sen's preference for deliberative public reasoning tailored to context.[1] This incompleteness, while philosophically flexible, risks vagueness in operationalization: capabilities must be normatively valuable yet avoid paternalism in imposing judgments on what individuals should value, and cultural or adaptive preferences can distort assessments of true potential.[3] Critics highlight that without clear boundaries, quantification efforts may conflate subjective valuations with objective metrics, undermining comparability across individuals or societies.[4] Valuation of capabilities as freedoms introduces additional complexity, as standard economic methods like willingness-to-pay or time trade-offs struggle to capture the intrinsic worth of expanded choice sets beyond achieved outcomes.[43] For instance, questionnaires attempting to elicit capability sets often fail to represent the full combinatorial nature or the value of unchosen options, leading to incomplete or biased proxies.[4] These conceptual tensions explain why empirical applications frequently resort to measuring functionings or resource proxies as stand-ins, though this dilutes the approach's focus on freedom and potential.[3]Key Indices and Their Construction
The Human Development Index (HDI), introduced by the United Nations Development Programme (UNDP) in 1990 and inspired by Amartya Sen's capability framework, serves as a composite measure approximating human capabilities through achievements in health, education, and living standards.[44] It normalizes indicators—life expectancy at birth (minimum 20 years, maximum 85), mean years of schooling (for adults over 25) and expected years (minimum 0, maximum 18), and gross national income per capita (PPP, log-transformed with minimum $100, maximum $75,000)—then computes a geometric mean to equalize dimensions and penalize imbalances.[44] While HDI shifts focus from GDP to capability-relevant outcomes, Sen critiqued it for relying on average achievements rather than individual freedoms and conversion factors, treating income as a proxy without accounting for interpersonal variations.[45] The Global Multidimensional Poverty Index (MPI), developed by Sabina Alkire and James Foster in 2010 and explicitly grounded in Sen's capability approach, quantifies acute poverty as deprivations in basic capabilities across health, education, and living standards.[46] It employs the Alkire-Foster method: households are deemed multidimensionally poor if deprived in at least one-third of weighted indicators (33% cutoff), with the MPI score as the product of the headcount ratio (incidence, H) and average intensity (A) of deprivations.[46] The 10 indicators include nutrition and child mortality (health, each one-third weight); years of schooling and child school attendance (education, each one-sixth); and cooking fuel, sanitation, drinking water, electricity, housing, and assets (living standards, each one-eighteenth).[46] Data from Demographic and Health Surveys enable annual global estimates, covering over 100 countries, but the fixed list and equal weighting have drawn criticism for not fully reflecting context-specific capabilities or agency.[47]| Index | Dimensions/Indicators | Construction Method | Capability Relation |
|---|---|---|---|
| HDI | Health (1), Education (2), Income (1) | Geometric mean of normalized indices | Proxies functionings as capability achievements; income as opportunity proxy[44] |
| MPI | Health (2), Education (2), Living Standards (6) | H × A with deprivation cutoffs and weights | Direct deprivations in basic capabilities; adjusts for intensity[46] |