跳到正文
← 返回论文列表与筛选
阅读说明

本页整理公开书目信息,不生成学术质量评分。AI 解读根据题名及所注明的摘要或原文片段生成,未完成全文核验,可能有误;具体假设、证明与结论请核对原文。摘要保留来源文本,未经模型改写。

DOI 首次登记不等于接收或发表日期。部分更正、评论等条目没有独立摘要;缺少可靠材料时保留待补状态。

本页为预印本版本;arXiv 收录、作者填写的期刊信息以及作者既有发表经历,都不单独证明本篇已接收。作者发表记录按 OpenAlex 身份与完整姓名、本站覆盖期刊 ISSN 及正式卷期核对,只展示已核实例,档案仍可能误合并。

引用量采用 OpenAlex 单条关联记录,不合计多个记录;关联记录可能包含正式发表版本,不等于此版本单独引用。缺失不视为零,引用指标不代表论文质量。

关注作者按书目中的完整姓名匹配,同名和姓名变体需人工辨别。相关论文先按共享细分方向和具体方法排列,再参考通用方法与发表日期。

分类依据与纠错

AI 根据所提供的论文材料归类:摘要研究错位处理下的双重差分、双向固定效应与匹配后因果估计,涉及因果推断和面板数据。

反馈分类问题

正在核对关联版本…

代码、数据与补充材料

正在核对对应版本的资源…

关注这篇论文的作者
Yihong Liu

匹配后的双向固定效应估计

研究问题
在条件平行趋势背景下,先按不随时间变化的协变量匹配、再进行双向固定效应回归,会带来哪些偏差和推断问题?
方法与思路
作者分析按匹配次数加权的双向固定效应估计,提出各处理批次分别与从未处理组比较的匹配后双重差分方法。
材料陈述的贡献
摘要称,错位处理时合并批次可在恒定效应下仍产生渐近偏差;作者给出替代估计量的一致性条件及计入匹配变异的标准误。
阅读关注点
应核对合并批次产生偏差的机制、替代估计量对应的因果参数、匹配设计要求,以及标准误如何纳入第一步的不确定性。
阅读边界
依据 arXiv 预印本摘要,同行评审或期刊接收未核实;一致性的具体条件与应用结果未说明,不能据此否定所有匹配后回归。

原文摘要

When estimating treatment effects with two-way fixed effects (2WFE) models, researchers often use matching as a pre-processing step when the parallel trends assumption is thought to hold conditionally on covariates. Specifically, in a first step, each treated unit is matched to one or more untreated units based on observed time-invariant covariates. In the second step, treatment effects are estimated with a 2WFE regression in the matched sample, reweighting the untreated units by the number of times they are matched. We formally analyze this common practice and highlight two problems. First, when different treatment cohorts enter treatment in different time periods, the post-matching 2WFE estimator that pools all treated cohorts has an asymptotic bias, even when the treatment effect is constant across units and over time. Second, failing to account for the variability introduced by the matching procedure yields invalid standard error estimators, which can be biased upwards or downwards depending on the data generating process. We propose simple post-matching difference-in-differences estimators that compare each treated cohort to the never-treated separately, instead of pooling all treated cohorts. We provide conditions under which these estimators are consistent for well-defined causal parameters, and derive valid standard errors that account for the matching step. We illustrate our results with simulations and with an empirical application.

笔记与分组
相关领域论文