When existing clinical trial data suggest a promising subgroup, we must address the question of how good the selected subgroup really is. The usual statistical inference applied to the selected subgroup, assuming that the subgroup is chosen independent of the data, will lead to overly optimistic evaluation of the selected subgroup. In this talk, we address the risk of greedy subgroup pursuit and propose quantitative analysis protocols that can help evaluate the potential of selected subgroups. In particular, we propose a new bootstrap-based inference procedure for the best selected subgroup effect. The proposed inference procedure is model-free, easy to compute, and asymptotically sharp. We demonstrate the merit of our proposed method by re-analyzing the MONET1 trial and show how the subgroup is selected post hoc should play an important role in any statistical analysis.
Xuming He is H.C. Carver Professor and Chair of Statistics at the University of Michigan. His prior appointments include faculty positions at National University of Singapore and University of Illinois at Urbana-Champaign. His research interests include theory and methodology in robust statistics, semiparametric models, quantile regression, data depth, dimension reduction, and subgroup analysis. His interdisciplinary research aims to promote the better use of statistics in biosciences, climate studies, concussion research, and social-economic studies. Xuming He is Fellow of the American Association for the Advancement of Science, the American Statistical Association, the Institute of Mathematical Statistics, and the International Statistical Institute. He served as Program Director of Statistics at the National Science Foundation, USA, Co-Editor of the Journal of the American Statistical Association, and Chair of the Scientific Program Committee, 2013 World Statistics Congress. He was IMS Medallion Lecturer and Keynote Speaker at the 2007 Joint Statistical Meetings, Plenary Speaker at the 21st International Conference on Computational Statistics (COMPSTAT 2014), and IASC President Invited Lecturer at the 62nd ISI World Statistics Congress in 2019. In 2015, he received the Distinguished Achievement Award from the International Chinese Statistical Association. He is a mentor of about 30 PhD students in Statistics, and his former students have received IMS Tweedie New Researcher Award and the ASA Noether Junior Scholar Award.