Sullivan’s research examines the consumption, saving and borrowing behavior of poor households in the U.S., and how welfare and tax policy affects the well-being of the poor. He is a research affiliate of the National Poverty Center, and his most recent work examines changes in consumption and income poverty in the U.S. over the past three decades. His research has been supported by grants from the Smith Richardson Foundation, the Annie E. Casey Foundation, and the National Bureau of Economic Research. He was a recipient of the W. E. Upjohn Institute for Employment Research Dissertation Award in 2003. His work has been published in the American Economic Review and in the and Journal of Policy Analysis Management, among others.