Overview
Robert Moffitt is the Krieger-Eisenhower Professor of Economics at Johns Hopkins University and a Research Associate at NBER. He is one of the leading scholars of the U.S. welfare system, low-income labor markets, and benefit program incentives, and served as editor of the Journal of Human Resources for many years. His work spans methodological foundations of causal inference, incentive effects of transfer programs, and the political economy of welfare redistribution.
Key Contributions / Features
- Moffitt (2003, PDR) and Moffitt (2005, Demography): Companion methodological papers explaining the counterfactual framework, endogeneity, IV exclusion restrictions, LATE, and the internal/external validity tradeoff to a population research audience. The 2005 paper is the full-length version, adding the formal structural equations (Y = α + βᵢT + γX + ε; T = δ + θX + φZ + υ), the area fixed-effects IV model (ΔY, ΔT, ΔZ as first differences), a named distinction between the area FE and population-segment FE designs, and a two-type analysis of extrapolation failure (mechanism specificity and range restriction). Both papers argue for synthetic evidence-weighing over method fetishism and caution against maximizing internal validity at the expense of external validity.
- Moffitt (2015, Demography) — PAA Presidential Address: Documents that U.S. means-tested spending tripled in real per capita terms 1970–2007, but was redistributed: elderly, disabled, and married-parent families gained; single-parent families and the deeply poor lost. Attributes this to the centuries-old Deserving Poor ideological distinction (workers, married adults, and parents = deserving; nonworkers, single parents, childless = undeserving). Identifies AFDC caseload composition shift from widows to never-married mothers as the proximate trigger of 1996 welfare reform.
- Ben-Shalom, Moffitt, and Scholz (2012): Systematic SIPP-based accounting of changes in anti-poverty program benefits by demographic group, 1983–2004; the primary empirical foundation for the 2015 redistribution findings.
- Welfare reform research: Extensive contributions on the incentive effects of AFDC/TANF, Medicaid, food stamps, and related programs on labor supply and family structure; editor of the NBER volume Means-Tested Transfer Programs in the United States (2003).
- Journal of Human Resources editorship: Long-serving editor who shaped standards for empirical identification in labor economics.
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