Nonrandom Exposure to Exogenous Shocks

• 成果类型: Article
• 署名作者: Borusyak, Kirill; Hull, Peter
• 署名单位: University of California System; University of California Berkeley; Centre for Economic Policy Research - UK; Brown University; University of Cambridge
• 刊物名称: ECONOMETRICA
• ISSN/ISSBN: 0012-9682
• DOI: 10.3982/ECTA19367
• 发表日期: 2023
• 页码: 2155-2185
• 关键词: randomized experiments; propensity score; variance; DESIGN; HEALTH; bounds; IMPACT

摘要

We develop a new approach to estimating the causal effects of treatments or instruments that combine multiple sources of variation according to a known formula. Examples include treatments capturing spillovers in social or transportation networks and simulated instruments for policy eligibility. We show how exogenous shocks to some-but not all-determinants of such variables can be leveraged while avoiding omitted variables bias. Our solution involves specifying counterfactual shocks that may as well have been realized and adjusting for a summary measure of nonrandomness in shock exposure: the average treatment (or instrument) across shock counterfactuals. We use this approach to address bias when estimating employment effects of market access growth from Chinese high-speed rail construction.