Bias-Variance Tradeoff of Matching Prior to Difference-in-Differences When Parallel Trends is Violated
平行趋势违反时双重差分前匹配的偏差—方差权衡
Quasi-experimental causal inference methods have become central in empirical operations management for guiding managerial decisions. Among these, empiricists utilize the Difference-in-Differences (DiD) estimator, which relies on the parallel trends assumption. To improve its plausibility, researchers often match treated and control units before applying DiD, with the intuition that matched groups are more likely to evolve similarly absent treatment. Existing work that…