Thursday, May 1st
11:45am - 1:00pm, ARB Hess Commons
Qing Pan, PhD
Professor, Department of Biostatistics and Bioinformatics
George Washington University, Milken Institute School of Public Health
Robust Weights for Prediction Transportability Under Covariate Shift
We study prediction transportability, where models built on a source sample with covariate shift are used to predict outcomes for a target population with unavailable responses. Propensity score weighting is a common approach, but its effectiveness is often compromised by extreme weights with high variance, sometimes performing worse than unweighted models. To address this, we propose a two-step importance-sampling and bootstrap procedure. We highlight key differences between robust methods in causal inference and those in prediction transportability. Through simulations, we generate source and target samples using distinct mechanisms and evaluate the original and two-step weighted models under propensity score and/or outcome model misspecification. Various overlap metrics between the source and target samples are examined, and the performance of the weighting methods is compared across different degrees of overlap. The proposed method performs comparably to standard weighting when models are correctly specified and shows significant improvement under misspecification. We discuss the advantages and limitations of the two-step procedure to guide method selection based on data characteristics.
Biostatistics Departmental Seminars & Lectures
Lectures are in-person only unless marked otherwise.
For all Zoom inquiries to attend seminars with a listed virtual option, please send an email to Erin Elliott, Programs Coordinator (ee2548@cumc.columbia.edu).
During the Fall and Spring semesters, the Department of Biostatistics holds regular seminars on Thursdays, called the Levin Lecture Series, on a wide variety of topics which are of interest to both students and faculty. Over each semester, there are also often guest lectures outside the regular Thursday Levin Lecture Series, to provide a robust schedule the covers the wide range of topics in Biostatistics. The speakers are invited guests who spend the day of their seminar discussing their research with Biostatistics faculty and students.
