Data Science / Statistics Seminar: Ana Maria Kenney (UC Irvine)

Speaker: Ana Maria Kenney, Assistant Professor, Department of Statistics, UC Irvine

Title: Distilling heterogeneous treatment effects: Stable subgroup estimation in causal inference

Abstract: Recent methodological developments have introduced new black-box approaches to better estimate heterogeneous treatment effects; however, these methods fall short of providing interpretable characterizations of the underlying individuals who may be most at risk or benefit most from receiving the treatment, thereby limiting their practical utility. In this work, we introduce a novel method, causal distillation trees (CDT), to estimate interpretable subgroups. CDT allows researchers to fit any machine learning model of their choice to estimate the individual-level treatment effect, and then leverages a simple, second-stage tree-based model to “distill” the estimated treatment effect into meaningful subgroups. As a result, CDT inherits the improvements in predictive performance from black-box machine learning models while preserving the interpretability of a simple decision tree. We derive theoretical guarantees for the consistency of the estimated subgroups using CDT, and introduce stability-driven diagnostics for researchers to evaluate the quality of the estimated subgroups. We illustrate our proposed method on a randomized controlled trial of antiretroviral treatment for HIV from the AIDS Clinical Trials Group Study 175 and show that CDT out-performs state-of-the-art approaches in constructing stable, clinically relevant subgroups.

Bio: Ana Maria Kenney is an Assistant Professor in the Department of Statistics at UC Irvine. She works at the interface of statistics, interpretable machine learning, and large-scale optimization to advance biomedical research. She has been on several interdisciplinary teams across institutions spanning cardiovascular genetics, “Omics” contributions to early infant growth, and early cancer screening. She completed a postdoc at UC Berkeley and previously received a dual title Ph.D. at Penn State in Statistics and Operations Research. There she was a Biomedical Big Data to Knowledge Training Fellow and Alfred P. Sloan Ph.D. Scholar.