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Should development policy treat people primarily as productive inputs whose education and health yield economic returns, or as free agents whose well-being is defined by their real opportunities to live lives they have reason to value? This tension between instrumental and intrinsic views of human development has driven the subfield of human capital development since its emergence. Three major frameworks have shaped the debate: Human Capital Theory, the Capabilities Approach, and Experimental Development Economics. Each arose in response to the limitations of its predecessors, and each continues to occupy a distinct role in research and policy today.
Human Capital Theory emerged in the early 1960s, principally through the work of Theodore Schultz and Gary Becker. Its central claim was that spending on education, health, and training is not merely consumption but investment in a stock of productive capacities—human capital—that yields future returns for individuals and societies. This idea broke sharply with classical and neoclassical traditions that treated labor as a homogeneous, interchangeable input. By showing that schooling raised earnings and that health improvements boosted productivity, Human Capital Theory provided a rigorous microeconomic foundation for public spending on social sectors.
The framework’s distinctive contribution was to make the development of people legible to cost-benefit analysis. Governments could now calculate the rate of return to an extra year of schooling or a vaccination campaign, compare it with returns to physical infrastructure, and allocate resources accordingly. This instrumental logic dominated development policy from the 1960s through the 1980s, shaping World Bank lending, national education plans, and the expansion of primary health systems. Yet the very success of Human Capital Theory also exposed its limits: by valuing people only for what they could produce, it left no room for the idea that development should expand human freedoms as an end in itself.
The Capabilities Approach, pioneered by Amartya Sen in the 1980s and later extended by Martha Nussbaum, emerged as a direct normative challenge to Human Capital Theory. Sen argued that the goal of development should be the expansion of people’s capabilities—their real freedom to achieve functionings they have reason to value—rather than the accumulation of human capital. Where Human Capital Theory asked “How much can this person produce?”, the Capabilities Approach asked “What is this person actually able to do and be?”
This was not a rejection of the importance of education or health, but a re-framing of their purpose. A literate, healthy person is valuable not only because she can work more productively, but because literacy and health enable her to participate in political life, care for her family, and pursue her own projects. The Capabilities Approach thus absorbed the core insights of Human Capital Theory—that schooling and health matter—while insisting that they matter for reasons that go beyond economic output. It also introduced a pluralistic metric of well-being: instead of a single measure like income or earnings, development should be assessed across multiple dimensions of functioning.
The Capabilities Approach coexisted with Human Capital Theory rather than replacing it. In policy circles, the two frameworks often operated in parallel: Human Capital Theory guided project-level cost-benefit analysis, while the Capabilities Approach informed broader goal-setting, most notably in the United Nations Human Development Index. Yet the tension between them remained. Human Capital Theory’s instrumentalism could justify cutting programs whose economic returns were low, even if those programs expanded freedoms in non-economic ways. The Capabilities Approach, by contrast, resisted any reduction of human development to a single monetary metric.
By the mid-1990s, a third framework entered the subfield, this time driven by methodological rather than normative concerns. Experimental Development Economics, associated with Esther Duflo, Abhijit Banerjee, and Michael Kremer, argued that the evidence base for both Human Capital Theory and the Capabilities Approach was too weak to guide policy. Correlational studies could not distinguish whether schooling caused higher earnings or whether people who would have earned more anyway also chose more schooling. The solution was to use randomized controlled trials (RCTs) to measure the causal impact of specific interventions.
Experimental Development Economics did not directly challenge the goals of either earlier framework. Instead, it narrowed the question from “Should we invest in human capital?” to “Which specific investments, delivered in which way, actually produce measurable improvements in education, health, or income?” This shift had profound consequences. Deworming treatments, for example, turned out to be a highly cost-effective way to improve school attendance—a finding that Human Capital Theory could readily incorporate into its cost-benefit calculations. But the experimental method also created friction with the Capabilities Approach, whose broad, multidimensional outcomes are difficult to capture in a single RCT. A program that expands women’s agency or strengthens community participation may not show up in test scores or earnings, yet the Capabilities Approach would count it as genuine development.
All three frameworks remain active in the subfield today, but they occupy different institutional and analytical niches. Human Capital Theory continues to dominate the economics of education and health, where researchers estimate private and social returns to investment and governments use those estimates to set budgets. The Capabilities Approach has found its strongest home in human development reporting, feminist economics, and the measurement of multidimensional poverty, where its pluralistic metric provides an alternative to GDP. Experimental Development Economics has become the dominant methodological paradigm for evaluating specific programs, especially in partnership with governments and NGOs in low-income settings.
Where the frameworks overlap, their assumptions often conflict. Human Capital Theory and Experimental Development Economics share a commitment to quantitative, outcome-oriented analysis, but they disagree on what counts as evidence: Human Capital Theory relies on observational data and structural models, while Experimental Development Economics insists on causal identification through randomization. The Capabilities Approach, meanwhile, is skeptical of both frameworks’ tendency to reduce human development to a set of measurable indicators, arguing that the most important capabilities—dignity, political voice, cultural belonging—resist easy quantification.
Despite these disagreements, the three frameworks have also learned from one another. Human Capital Theory has incorporated experimental findings to refine its estimates of returns to specific interventions. The Capabilities Approach has influenced the choice of outcomes that experimentalists measure, pushing them beyond test scores and earnings toward indicators of empowerment and well-being. And Experimental Development Economics has provided the Capabilities Approach with rigorous evidence that some of its favored policies—such as conditional cash transfers—do in fact improve health and education, even if they do not capture the full range of capabilities.
The history of human capital development in development economics is not a story of one framework replacing another. It is a story of persistent tension between two visions of development: one that sees people as instruments of growth and another that sees growth as an instrument for expanding human freedom. Human Capital Theory gave the subfield its first rigorous analytical tools. The Capabilities Approach insisted that those tools were not enough. Experimental Development Economics demanded that both frameworks prove their claims with credible evidence. Today, researchers and policymakers must navigate among all three, choosing the framework that best fits the question at hand while remaining aware of what each leaves out.