6 papers
Externally Controlled Trials: A Review of Design and Borrowing Through a Causal Lens
Ke Zhu, Rima Izem, Peng Yang +8
Externally controlled trials (ECTs) are increasingly used when randomized controls are infeasible, unethical, or insufficient, including applications in rare diseases, oncology, pe…
Design-based theory for causal inference
Xin Lu, Wanjia Fu, Hongzi Li +4
Causal inference, as a major research area in statistics and data science, plays a central role across diverse fields such as medicine, economics, education, and the social science…
Sharp variance estimator and causal bootstrap in stratified randomized experiments
Haoyang Yu, Ke Zhu, Hanzhong Liu
Randomized experiments are the gold standard for estimating treatment effects, and randomization serves as a reasoned basis for inference. In widely used stratified randomized expe…
Rejoinder to Reader Reaction "On exact randomization-based covariate-adjusted confidence intervals" by Jacob Fiksel
Ke Zhu, Hanzhong Liu
We applaud Fiksel (2024) for their valuable contributions to randomization-based inference, particularly their work on inverting the Fisher randomization test (FRT) to construct co…
Imputation-based randomization tests for randomized experiments with interference
Tingxuan Han, Ke Zhu, Hanzhong Liu +1
The presence of interference renders classic Fisher randomization tests infeasible due to nuisance unknowns. To address this issue, we propose imputing the nuisance unknowns and co…
Design-based theory for Lasso adjustment in randomized block experiments and rerandomized experiments
Ke Zhu, Hanzhong Liu, Yuehan Yang
Blocking, a special case of rerandomization, is routinely implemented in the design stage of randomized experiments to balance the baseline covariates. This study proposes a regres…