Jiajun Liu

Journal article Stat Biosci · September 15, 2025 Common variance estimation methods for weighted average treatment effects (WATEs) in observational studies include nonparametric bootstrap and model-based, closed-form sandwich variance estimation. However, the computational cost of bootstrap increases wit ... Full text Open Access Link to item Cite

Assessing racial disparities in healthcare expenditure using generalized propensity score weighting.

Journal article BMC Med Res Methodol · March 7, 2025 PURPOSE: This paper extends current propensity score weighting methods for causal inference to better understand disparities in healthcare access across multiple racial groups. By treating each racial group as a distinct entity (or "treatment") in the caus ... Full text Open Access Link to item Cite

Statistical Evaluation of Responder Analysis in Stem Cell Clinical Trials.

Journal article Ther Innov Regul Sci · November 2023 BACKGROUND: In evaluating treatment efficacy, there is an ongoing discussion about which endpoint is more efficient to represent the treatment effect. Absolute change (AC) is the difference between before and after treatment, while relative change (RC) is ... Full text Link to item Cite

A Proposal for Post Hoc Subgroup Analysis in Support of Regulatory Submission.

Journal article Ther Innov Regul Sci · March 2023 BACKGROUND: In clinical trials, it is not uncommon that the primary analysis fails to achieve the study objective for demonstrating the safety and efficacy of a test treatment under investigation, while a specific sub-population analysis shows a significan ... Full text Open Access Link to item Cite