Overview
Yu Xie is Henry Putnam University Professor of Sociology at Princeton University and co-director of the Office of Population Research. His research spans social stratification and inequality in the United States and China, statistical methods for causal inference in social science, and the sociology of science. He co-developed with Xie and Wu (2005) the hierarchical linear model (HLM) approach to studying heterogeneous treatment effects via propensity-score stratification — the method used in Brand and Xie (2010) to document negative selection in college wage returns.
Key Contributions / Features
- HLM approach to treatment-effect heterogeneity (Xie and Wu 2005): Co-developed a two-level HLM framework where Level 1 estimates treatment effects within propensity-score strata and Level 2 models the trend in those effects across strata, enabling a direct test of positive vs. negative selection.
- Negative selection in college returns (Brand and Xie 2010): Co-authored American Sociological Review paper using NLSY79 and WLS data to show that individuals least likely to attend college benefit most from doing so — 10 consistent negative Level-2 slopes across datasets, sexes, and life-course stages. Won ASA James Coleman Award (2012) and ASA Inequality, Poverty, and Mobility Distinguished Article Award (2011).
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