English

Limit theorems of matching estimators with a fixed number of matches

Statistics Theory 2026-05-21 v2 Econometrics Statistics Theory

Abstract

This paper re-examines the limit theorems of Abadie and Imbens for nearest-neighbor matching estimators of average treatment effects with a fixed number of matches. We establish, for the first time, a non-normalized central limit theorem (CLT) with an explicitly calculated limiting variance. The key ingredients are to prove the convergence of the normalizing statistic appearing in the CLT of Abadie and Imbens to its mean, and to calculate the closed form of the limit of this mean. The former closes a gap in the argument of an unpublished work (Abadie and Imbens, 2002), while the latter resolves a question raised in Abadie and Imbens (2006).

Keywords

Cite

@article{arxiv.2411.05758,
  title  = {Limit theorems of matching estimators with a fixed number of matches},
  author = {Songliang Chen and Fang Han},
  journal= {arXiv preprint arXiv:2411.05758},
  year   = {2026}
}

Comments

In this version, we close a gap in the original submission