Unbiased Regression-Adjusted Estimation of Average Treatment Effects in Randomized Controlled Trials
随机对照试验中平均处理效应的无偏回归调整估计
This article introduces a leave-one-out regression adjustment (LOORA) for estimating average treatment effects in randomized controlled trials. In finite samples, LOORA removes the bias of conventional regression adjustment and yields exact variance formulas for regression-adjusted Horvitz-Thompson and difference-in-means estimators. Ridge regularization curbs the influence of high-leverage observations, improving stability and precision in small samples. In large samples,…