Quasi-Experimental Shift-Share Research Designs

• 成果类型: Article
• 署名作者: Borusyak, Kirill; Hull, Peter; Jaravel, Xavier
• 署名单位: University of London; University College London; Centre for Economic Policy Research - UK; Brown University; National Bureau of Economic Research; University of London; London School Economics & Political Science
• 刊物名称: REVIEW OF ECONOMIC STUDIES
• ISSN/ISSBN: 0034-6527
• DOI: 10.1093/restud/rdab030
• 发表日期: 2022
• 页码: 181-213
• 关键词: import competition; US; instruments; immigration; rise

摘要

Many studies use shift-share (or Bartik) instruments, which average a set of shocks with exposure share weights. We provide a new econometric framework for shift-share instrumental variable (SSIV) regressions in which identification follows from the quasi-random assignment of shocks, while exposure shares are allowed to be endogenous. The framework is motivated by an equivalence result: the orthogonality between a shift-share instrument and an unobserved residual can be represented as the orthogonality between the underlying shocks and a shock-level unobservable. SSIV regression coefficients can similarly be obtained from an equivalent shock-level regression, motivating shock-level conditions for their consistency. We discuss and illustrate several practical insights of this framework in the setting of Autor et al. (2013), estimating the effect of Chinese import competition on manufacturing employment across U.S. commuting zones.