Kathleen Mullen is an economist at the RAND Corporation and associate director of the RAND Center for Disability Research. She is also a professor at the Pardee RAND Graduate School. Her work addresses the economics of retirement, health, and disability, with an emphasis on the incentive effects of social insurance programs such as Social Security and Social Security Disability Insurance (SSDI). In her research, Mullen has employed a variety of research designs applying both reduced form and structural econometric methods. She has pursued research on, among other things, the effects of SSDI receipt on labor supply; the effects of long waiting times on the subsequent labor force participation and earnings of rejected SSDI applicants; how changes in eligibility requirements affect SSDI or Social Security claiming; and the effects of changes in Social Security or disability insurance incentives in other countries on labor supply for workers at older ages, and what those findings suggest about potential evaluations of reforms in the United States. Mullen received her Ph.D. in economics from the University of Chicago.

She joined IZA as a Research Fellow in August 2014.