Colloquium - Zhenke Wu - September 10, 2026

Speaker: Zhenke Wu, University of Michigan
Date/Time: Thursday, September 10, 2026, 10:00 AM - 11:00 AM ET

Title:  Ensuring Fairness in Sequential Decision Making: Counterfactual Fairness in Reinforcement Learning for Opioid Use Disorder Services

Abstract: As healthcare systems move to deploy reinforcement learning (RL) for dynamic resource allocation, significant concerns have been raised about the impact of these tools on health services access and equity. While RL may improve service personalization, black-box optimization based on historical data can inadvertently lead to withholding needed treatment from vulnerable subgroups. We investigated the impact on fairness in treatment allocation using clinical data from a study that tested an RL-supported intervention for managing chronic pain and opioid misuse risk. In this talk, I show how to (1) audit standard RL policies for allocation bias across patient subgroups, and (2) validate a deployable methodology for correcting identified disparities without compromising clinical outcomes. We show that standard methodologies seeking to achieve “fairness through unawareness” are insufficient. Our framework evaluates and patches these vulnerabilities prior to deployment, satisfying a key requirement for the ethical scaling of AI in healthcare. Although motivated by health applications, the proposed framework applies in broader operations management contexts.

Bio: Dr. Zhenke Wu is an Associate Professor of Biostatistics and Global Public Health at the University of Michigan. Dr. Wu's current research focuses on reinforcement learning, Bayesian methods, causal inference, AI and statistics, some of which inform the development of digital and mobile health interventions. In addition to his research, Dr. Wu serves as an Associate Editor for Biostatistics, Annals of Applied Statistics, and Journal of the Royal Statistical Society – Series A, and as a standing statistical editor for NEJM AI. Dr. Wu earned his bachelor's degree in mathematics from Fudan University (2009) and his PhD in biostatistics from Johns Hopkins University (2014).

Website: https://zhenkewu.com/