Gene-Environment Interactions with Essential Heterogeneity

• 成果类型: Article; Early Access
• 署名作者: Hollenbach, Johannes; Schmitz, Hendrik; Westphal, Matthias
• 署名单位: Leibniz Association; RWI - Leibniz Institut fur Wirtschaftsforschung; University of Paderborn; Fern University Hagen
• 刊物名称: ECONOMIC JOURNAL
• ISSN/ISSBN: 0013-0133
• DOI: 10.1093/ej/ueag010
• 发表日期: 2026
• 关键词: instrumental variables; health-evidence; SCHOOLING LAWS; education; returns; identification; EQUATIONS; average; models; recall

摘要

We study how gene-environment interactions between education and genetic endowments affect cognition in old age, and we use this setting to show that-even with a valid instrument-two-stage least-squares estimates of interaction effects can be far from the true effect. This occurs when treatment effects are heterogeneous and compliance with the instrument depends on the interaction variable. We suggest estimating marginal treatment effects to address this problem. Our estimation results show complementarities between education and genetic predisposition in determining later-life memory. The marginal treatment effect estimates suggest substantially larger gene-environment interactions than the two-stage least-squares estimates.