4 papers
Robust and Efficient Semiparametric Inference for the Stepped Wedge Design
Fan Xia, K. C. Gary Chan, Emily Voldal +3
Stepped wedge designs (SWDs) are increasingly used to evaluate longitudinal cluster-level interventions but pose substantial challenges for valid inference. Because crossover times…
Dimension-reduced outcome-weighted learning for estimating individualized treatment regimes in observational studies
Sungtaek Son, Eardi Lila, Kwun Chuen Gary Chan
Individualized treatment regimes (ITRs) aim to improve clinical outcomes by assigning treatment based on patient-specific characteristics. However, existing methods often struggle…
The Categorical Instrumental Variable Model: Characterization, Partial Identification, and Statistical Inference
Yilin Song, F. Richard Guo, K. C. Gary Chan +1
We study categorical instrumental variable (IV) models with instrument, treatment and outcome taking finitely many values. We derive a simple closed-form characterization of the se…
GMM with Many Weak Moment Conditions and Nuisance Parameters: General Theory and Applications to Causal Inference
Rui Wang, Kwun Chuen Gary Chan, Ting Ye
Weak identification arises in many statistical problems when key variables exhibit weak correlations-for example, when instrumental variables correlate weakly with treatment, or wh…