Econometrics Seminar Series. "Trading-off Bias and Variance When the Size of the Treatment Effect is Bounded"
Published: 6 November 2025
28 November. Professor Clément de Chaisemartin, Sciences Po
Professor Clément de Chaisemartin, Sciences Po
"Trading-off Bias and Variance When the Size of the Treatment Effect is Bounded"
Friday, 28 November. 15:00 -16:30
Online
Abstract
Assume that one is interested in estimating an average treatment effect (ATE), equal to a weighted average of S conditional average treatment effects (CATEs). One has unbiased estimators of the CATEs. One could just average the CATE estimators, to form an unbiased estimator of the ATE. However, some CATE estimators may be less precise than others. Then, downweighting the imprecisely estimated CATEs may lead to a lower mean-squared error and/or shorter confidence intervals. This paper investigates this bias-variance trade-off, by deriving minimax linear estimators of, and confidence intervals (CI) for, the ATE, under various restrictions on the CATEs. First, I assume that the magnitude of the CATEs is bounded. Then I assume that their heterogeneity is bounded. I use my results to revisit two empirical applications, and find that minimax-linear estimators and CIs lead to small but non-negligible precision gains.
Bio
Clément de Chaisemartin is Professor of Economics at the Department since 2021. He is an Associate Professor at the University of California at Santa Barbara (UCSB), currently on leave. He is also a Faculty Research Fellow at the National Bureau of Economic Research (NBER) and a JPAL Affiliate.
His research interests focus on econometric methods for policy evaluation and on the economics of education. His work has been published in several international journals, including the American Economic Review, Econometrica, the Review of Economic Studies, Quantitative Economics, the American Economic Journal: Applied Economics, and Clinical Infectious Diseases.
In 2019, his paper "Fuzzy Differences-in-Differences", published in the Review of Economic Studies, received the AFSE-Malinvaud Prize. He has been awarded a number of research grants by the French health and education authorities, and has carried out several randomized controlled trials evaluating educational interventions, in France and in Chile.
Clément de Chaisemartin holds a PhD in Economics (’13) from the École des Hautes Études en Sciences Sociales (EHESS) and the Paris School of Economics (PSE). Prior to joining the Department, he was a permanent faculty member at the University of Warwick and then UCSB.
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First published: 6 November 2025