Capabilities and human development
Development should be measured by what people are actually able to do and to be, because income and even goods say nothing about what a particular person can convert them into.
Amartya Sen, Mahbub ul Haq, Martha Nussbaum · Credits and sources ↓
What it says
Sen's opening move is a question about measurement: equality of what? Income treats a rupee as a rupee whoever holds it. Utility treats satisfaction as the currency, which means a person who has adapted to deprivation and stopped wanting much scores well. Goods themselves are no better, because the same bicycle gives mobility to one person and nothing to another.
The answer is to evaluate at the level of functionings, the things a person actually manages to do and be, and capabilities, the set of functionings genuinely open to them. What sits between a resource and a functioning is a conversion factor: a disability, a caste rule about who may draw water, a road that floods, a norm about where a woman may walk after dark. Two households with the same income can have entirely different capability sets, and the difference is not a matter of preference.
Haq's contribution was to make it operational and public. The first Human Development Report in 1990 opened by saying that people are the real wealth of a nation, and put a three-part index next to GDP: a long and healthy life, knowledge, and a decent standard of living. Sen was uneasy about compressing the idea into one number and joined anyway, on the argument that a crude index that competes with GNP is more use than a refined idea that does not.
With Jean Drèze, Sen then applied it to India across three books, and the argument that came out is about public action. India's record on the things the approach measures has lagged its record on income growth, and the gap is not explained by poverty alone, since poorer countries and poorer Indian states have done better on schooling, immunisation and child nutrition.
Drawn one step at a time
The theory as a graph, revealed a layer at a time. Use the buttons, or the left and right arrow keys. Each step adds the boxes that step introduces and the arrows into them.
- Starting condition
- Mechanism
- Outcome or policy
Four placements, and the reason for each
The four scores are editorial. They run from -3 to +3, they were assigned by the ImpactMojo editorial team from the theory's own texts, and each theory page shows the sentence that justifies its placement so the placement can be argued with. They are a way of arranging a shelf, not a measurement.
Public provision for health, education and social security, with markets left in place for most production. Sen has been consistently unwilling to treat the market itself as the enemy.
Distribution is the measurement, not a later correction. Growth matters because of what it buys, and the approach exists to keep asking whether it bought anything.
Conversion factors are where caste, gender and disability enter, and they enter as causes of different outcomes from the same resources. Sen's work on missing women and on cooperative conflict inside households is the clearest case.
Both, in a specific arrangement: public action means a state that provides and a public that argues, with democratic discussion doing the work of setting priorities.
The theory against the record
Each entry takes one claim the theory makes and reports what the evidence says about it, with a named source and a year. This section is the reason the library exists; a catalogue of positions without it is a reading list.
The claim Income growth does not carry human development with it automatically.
India is the standing example. Growth after 1991 was rapid and the improvement in child nutrition was not: the National Family Health Survey rounds recorded child stunting falling slowly from around 48 per cent in 2005-06 to roughly 38 per cent in 2015-16 and about 36 per cent in 2019-21, leaving India worse on this measure than countries with a fraction of its income per head. The pattern is old enough to have a name, the Asian enigma, given to it in 1996.
National Family Health Survey rounds 3, 4 and 5, Ministry of Health and Family Welfare; Ramalingaswami, Jonsson and Rohde on the Asian enigma · 2021
The claim A famine can happen without a fall in food availability.
The entitlement account of the 1943 Bengal famine has been argued over for forty years and has largely held, in the sense that nobody now explains the famine by supply alone. The sharpest challenges, including Bowbrick's, dispute Sen's specific availability figures rather than the general claim that exchange entitlements can collapse independently of supply, and the mechanism is now standard in famine early-warning practice.
Amartya Sen, Poverty and Famines; and the subsequent literature including Peter Bowbrick's critique · 1981
The claim A single index can move governments.
It did, and in a way that is measurable in behaviour rather than outcomes. National and state human development reports became routine, India's states began publishing their own, and the reporting of an HDI rank is now a fixed feature of the political argument. Whether the reporting improved the underlying numbers is a separate question the index cannot answer about itself.
UNDP Human Development Report series from 1990; Indian state human development reports · 1990
The claim Public provision, not income, does most of the work.
Supported by the within-India comparison that Drèze and Sen built the argument on. Kerala reached life expectancy and literacy levels far above what its income per head predicted, on a record of school provision, public health and land reform going back to the princely states and sustained by electoral competition. The comparison is genuinely informative and it is one case, which is the standing weakness of the argument.
Jean Drèze and Amartya Sen, India: Economic Development and Social Opportunity · 1995
What this does not settle
The approach is much better at evaluation than at prescription, and its own proponents say so. Knowing that a girl's schooling is blocked by a conversion factor does not say which instrument removes it, and the list of capabilities that matter is either left open, as Sen prefers, which makes it hard to use for policy, or specified, as Nussbaum does, which raises the question of whose list it is. What has not been resolved is the aggregation problem the Human Development Index papered over: the index weights three things equally because there is no principled way to weight them at all, and everyone involved knew that in 1990.
How it landed here
Two of the three people who built this were from the subcontinent and the Indian material is not an application but a source. The famine work is Bengal. The missing women calculation is South Asian demography. The public action argument was assembled from the difference between Kerala and Uttar Pradesh. It is also the theory with the deepest institutional presence here, through the state human development reports, the National Rural Employment Guarantee Act's rights framing, and the Right to Education, and that presence is itself worth noticing: an approach designed to resist a single number produced a single number, and the number is what travelled.
One that agrees, one that does not
Annihilation of caste and state socialism
Conversion factors and caste are the same observation from two directions: the same resource does different work depending on who holds it and where.
The stages of economic growth
Rostow's endpoint is high mass consumption. This approach exists to say that consumption is a means whose value depends entirely on what a particular person can do with it.
Whose theory this is
Amartya Sen born 1933
Built the argument across three decades, starting from a question about what equality is even measuring. The 1998 Nobel citation named welfare economics, social choice and the study of famine, which are the same project approached three times.
Mahbub ul Haq 1934–1998
Pakistani economist who had spent the 1960s building growth plans and concluded they measured the wrong thing. He turned Sen's philosophy into an index and an annual report, over Sen's initial objection that a single number would flatten the idea.
Martha Nussbaum born 1947
Argued, against Sen, that the approach needs a specified list of central capabilities if it is to ground claims of justice rather than only evaluation.
What ImpactMojo added
The causal diagram, the four placements and the notes justifying them, and the evidence section: what each claim predicted and what the record shows, with a named source and year for every entry.
ImpactMojo · content CC BY-NC-ND 4.0 · code MIT
Start with these
- Amartya Sen, Equality of What? (1979). The Tanner Lecture. Twenty pages, and the whole argument is already there.
- UNDP, Human Development Report 1990 (1990). Haq's report. The first chapter is a policy argument rather than a statistical annexe, and reads that way.
- Jean Drèze and Amartya Sen, India: Economic Development and Social Opportunity (1995). The approach applied to India, with the inter-state comparison that carries the public action argument.
Open access, in Development Discourses:
- Human Development Report 2023/24 — UNDP (2024)
- Acute Multidimensional Poverty: A New Index for Developing Countries — Sabina Alkire, Maria Emma Santos (2010)
- Counting and Multidimensional Poverty Measurement — Sabina Alkire, James Foster (2011)