The three development economists used randomized controlled trials (RCTs) to test interventions such as free medicine or remedial tutoring, isolating causal effects with statistical rigor. In Kenyan schools they showed that targeted help for weak students increased test scores far more than extra textbooks. In Indian villages, deworming pills were widely taken only when free, boosting school attendance and even long-run earnings. Their findings fed directly into WHO’s mass deworming advice and India’s large tutoring programs. By supplying hard evidence on what works, they guide scarce public funds toward the most effective poverty-reduction tools.

The laureates reconstructed “the economics of poverty” through micro-empirical work. While RCTs deliver strong internal validity, external validity and spillovers must be addressed. Linking experiments to theory—contract theory and behavioral economics—they identified mechanisms such as price elasticity, present bias, and incentive design. In the fertilizer study, a time-limited discount increased take-up more than a permanent subsidy, highlighting behavioral constraints in policy design. They also developed methods to estimate general-equilibrium and congestion effects during scale-up, creating a bridge from small trials to national programs. Development economics has thus pivoted toward experimentalism, and evidence-based policy making (EBPM) is now mainstream among governments and international agencies.

Banerjee, Duflo, and Kremer operationalized development economics as an applied micro-lab, institutionalizing field RCTs (e.g., PROGRESA, Pratham, Deworm the World). They refined identification under partial compliance with IV and LATE, addressed design-based clustering, and introduced saturation designs to quantify network externalities. Structural models—dynamic discrete choice with present bias—were layered onto reduced-form impacts to perform counterfactual welfare analysis. Spillover-robust variance estimators and ML-assisted heterogeneity searches can be traced to this research program. The RCT paradigm now shapes nationwide pilots, such as UBI cash-transfer experiments, evidencing their profound impact on empirical methodology and global poverty policy.