My research focuses on causal inference including:
Design and analysis of randomized experiments
randomization tests
covariate adjustment
rerandomization
analysis of clustered, split-plot, network experiments
Observational studies
sensitivity analysis for unmeasured confounding
overlap of covariates
integrating multiple data sources
Natural experiments
instrumental variable
difference-in-differences and panel data
regression discontinuity
Causal mechanisms
treatment effect variation
principal stratification, mediation analysis
interference
I am also fascinated by the following areas:
Survey sampling
Missing data: identification and estimation with data missing not at random
Measurement error
Properties of least-squares and its variants
Intersection of Frequentist and Bayesian statistics: Professor Carl Morris called it FB (Morris' football)
Applied statistics in social sciences and biometrical studies