Bartik Instruments: What, When. Why, and How

• 成果类型: Article
• 署名作者: Goldsmith-Pinkham, Paul; Sorkin, Isaac; Swift, Henry
• 署名单位: Yale University; Stanford University; National Bureau of Economic Research
• 刊物名称: AMERICAN ECONOMIC REVIEW
• ISSN/ISSBN: 0002-8282
• DOI: 10.1257/aer.20181047
• 发表日期: 2020
• 页码: 2586-2624
• 关键词: variables; inference; outcomes; IMPACT

摘要

The Bartik instrument is formed by interacting local industry shares and national industry growth rates. We show that the typical use of a Bartik instrument assumes a pooled exposure research design, where the shares measure differential exposure to common shocks, and identification is based on exogeneity of the shares. Next, we show how the Bartik instrument weights each of the exposure designs. Finally, we discuss how to assess the plausibility of the research design. We illustrate our results through two applications: estimating the elasticity of labor supply, and estimating the elasticity of substitution between immigrants and natives.