My research interests are in the areas of labor economics and applied microeconometrics, with a special focus on the economics of issues relating to the low-income population in the U.S.. A large portion of my research in labor economics has concerned the labor supply decisions of female heads of family and its response to the U.S. welfare system. My research on the welfare system has led to publications on the AFDC, Food Stamp, and Medicaid programs. I have also published research on the labor supply and family structure effects of social insurance programs, including Social Security, unemployment insurance, and disability insurance, as well as of the U.S. income tax system. Other papers have concerned trends in volatility in the U.S. labor market and trends in the labor force attachment of men and women. Part of my research also focuses on population economics and economic demography, where I have estimated economic models of marriage, cohabitation, female headship, and fertility. My methodological research has led to publications on selection bias and limited-dependent variable models, nonlinear budget constraints, panel data, attrition, duration models, and causal modeling and program evaluation.
I am the Krieger-Eisenhower Professor of Economics at Johns Hopkins University, where I have worked since 1995. I also hold a joint appointment at the Johns Hopkins Bloomberg School of Public Health. Prior to assuming my positions at Hopkins, I was Professor of Economics at Brown University, where I taught for eleven years. I have also been a visiting professor at the University of Wisconsin and the University of Maryland, and worked for several years at Mathematica Policy Research, Inc.
I am also a Fellow of the Econometric Society, a Fellow of the Society of Labor Economists, a member of the National Academy of Sciences, a recipient of a MERIT Award from the National Institutes of Health, a recipient of a Guggenheim Fellowship, a Fellow of the American Academy of Arts and Sciences, and Past President of the Population Association of America. I have served as Chief Editor of the American Economic Review, Coeditor of the Review of Economics and Statistics, Chief Editor of the Journal of Human Resources, and as Chair of the National Academy of Sciences Panel to Evaluate Welfare Reform. I am currently editor of Tax Policy and the Economy, a publication of the National Bureau of Economic Research which provides policy analysts in Washington with results from recent academic economic research on tax and transfer issues.
“Interview with University of Chicago, December 2018”
“HCEO Video on my Welfare Program Research”
"Covid-19 and the U.S. Safety Net", (September, 2020) [PDF Copy]
"Reconciling Trends in Volatility: Evidence from the SIPP Survey and Administrative Data", (July, 2020) [PDF Copy]
"Estimating Trends in Male Earnings Volatility with the Panel Study of Income Dynamics", (June, 2020) [PDF Copy]
"The Role of Ethnographic and Qualitative Research in Learning About the Low-Income Population", (June, 2019) [PDF Copy]
"The Marginal Labor Supply Disincentives of Welfare Reforms", (June, 2019) [PDF Copy]
“Semiparametric Estimation of the Canonical Permanent-Transitory Model of Earnings Dynamics”, Quantitative Economics, (November, 2019), (with Y.Hu and Y. Sasaki) [PDF Copy] [Supplement] [Stata Commands]
“The Extended Semiparametric (ESP) Model of Permanent-Transitory Decompositions of Earnings Variances”, (May, 2018) [PDF Copy]
Welfare Reform and the Labor Market (February, 2018) [PDF Copy]
Income Volatility and the PSID: Past Research and New Results (January, 2018) [PDF Copy]
Welfare Rules, Incentives, and Family Structure, Revised (Revised February, 2018) [PDF Copy]
Child Age and Gender Differences in Food Security in a Low-Income Inner-City Population (with D.Ribar) [PDF Copy]
Economics of Means-Tested Transfer Programs, Volumes I and II, 2016 [Vol 1 PDF Copy] [Vol 2 PDF Copy]
Policy and Other Papers:
Trends in the Distribution of Social Safety Net Support After the Great Recession (February, 2018) [PDF Copy]
Technical Panel on Labor Force Participation: Report to the Social Security Advisory Board (June, 2017) [PDF Copy]
Recent Research on the Distributional and Tax Rate Structure of the U.S. Welfare System (November, 2016) [PDF Copy]
Twenty Years After the Welfare to Work Act: Effects on Work and Poverty (September, 2016) [PDF Copy]
The U.S. Safety Net and Work Incentives: Is There a Problem? What Should be Done? (Fall, 2016) [PDF Copy]
Assessing the Need for a New Nationally Representative Household Panel Survey in the United States (April, 2015) [PDF Copy]
Unemployment Benefits and Unemployment, IZA World of Labor, 2015 [PDF Copy]
Evaluation Methods for Program Entry Effects (1992) [PDF Copy]
Trends in the Covariance Structure of Earnings in the U.S.: 1969-1987 (July 1995) [PDF Copy]
Printed in the Rediscovered Classics Series in the Journal of Economic Inequality (August, 2011)
Economics 355 - Economics of Poverty and Inequality
This course focuses on the economics of poverty and inequality. It covers the measurement of poverty and inequality, facts and trends over time, the causes of poverty and inequality with a focus on those related to earnings and the labor market, and public policy toward poverty and inequality, covering both taxation and government expenditure and programs. By the nature of the material, the course is fairly statistical and quantitative. Several sections make use of intermediate microeconomic concepts, so Economics 301 (intermediate microeconomics) is a prerequisite. Basic knowledge of regression analysis is also helpful.
Economics 651 -- Labor Economics:
This is a graduate survey course in labor economics. The course covers most of the classic topics in labor, including labor supply, labor demand, human capital, compensating wage differentials, and unemployment and job search. Reflecting the field, much of the material is empirical in nature and will use advanced econometric techniques.