English

On the inconsistency of matching without replacement

Econometrics 2021-06-21 v2 Statistics Theory Statistics Theory

Abstract

The paper shows that matching without replacement on propensity scores produces estimators that generally are inconsistent for the average treatment effect of the treated. To achieve consistency, practitioners must either assume that no units exist with propensity scores greater than one-half or assume that there is no confounding among such units. The result is not driven by the use of propensity scores, and similar artifacts arise when matching on other scores as long as it is without replacement.

Keywords

Cite

@article{arxiv.1907.07288,
  title  = {On the inconsistency of matching without replacement},
  author = {Fredrik Sävje},
  journal= {arXiv preprint arXiv:1907.07288},
  year   = {2021}
}