RISK SET MATCHED DIFFERENCE-IN-DIFFERENCES FOR THE ANALYSIS OF EFFECT MODIFICATION IN AN OBSERVATIONAL STUDY ON THE IMPACT OF GUN VIOLENCE ON HEALTH OUTCOMES

• 成果类型: Article
• 署名作者: Cohn, Eric R.; Song, Zirui; Zubizarreta, Jose R.
• 署名单位: Harvard University; Harvard T.H. Chan School of Public Health; Harvard University; Harvard University; Harvard University; Harvard University
• 刊物名称: ANNALS OF APPLIED STATISTICS
• ISSN/ISSBN: 1932-6157
• DOI: 10.1214/24-AOAS1918
• 发表日期: 2025
• 页码: 75-93
• 关键词: sensitivity-analysis; firearm injuries

摘要

Gun violence is a major source of injury and death in the United States. However, relatively little is known about the effects of firearm injuries on survivors and their family members and how these effects vary. To study these questions and, more generally, to address a gap in the methodological causal inference literature, we present a framework for the study of effect modification or heterogeneous treatment effects in difference-in-differences designs. We implement a new matching technique, combining profile matching and risk set matching to: (i) preserve the time alignment of covariates, exposure, and outcomes, avoiding pitfalls of other common approaches for difference-in-differences, and (ii) explicitly control biases due to imbalances in observed covariates in subgroups discovered from the data. Our case study shows significant and persistent effects of nonfatal firearm injuries on several health outcomes for those injured and on the mental health of their family members. Sensitivity analyses reveal that these results are moderately robust to unmeasured confounding bias. Finally, while the effects for those injured vary largely by the severity of the injury and its documented intent, for families, effects are strongest for those whose relative's injury is documented as resulting from an assault, self-harm, or law enforcement intervention.