标题： 边缘处的处理效应：每个人都是边际的 显示英文标题

标题： Treatment effects at the margin: Everyone is marginal

摘要： 本文提出了一种框架，用于识别当一项政策同时改变参与激励和感兴趣的结果时的处理效应——例如，针对就业补贴的招聘决策和工资；或针对职业培训的工作决策和工资。 该框架受到我关于比利时一项补贴首次雇佣的改革的博士项目启发，该改革促使边际企业进入市场，同时改变了它们支付的工资。 解决选择进入处理概念的标准方法（如 Heckman 选择方程和局部平均处理效应），或前后比较方法（包括简单的双重差分法或断点回归设计），无法在处理定义了观察对象的这一变动边界上隔离效应。 我引入了边际权重估计量，以恢复政策诱导进入者的因果效应，在存在内生选择的环境下提供一种政策相关的替代方案。 因此，该方法可以广泛应用于理解公共计划的经济影响，尤其是在主要依赖简化的形式因果推断估计的领域（例如，劳动经济学、发展经济学、健康经济学）。 显示英文摘要

摘要： This paper develops a framework for identifying treatment effects when a policy simultaneously alters both the incentive to participate and the outcome of interest -- such as hiring decisions and wages in response to employment subsidies; or working decisions and wages in response to job trainings. This framework was inspired by my PhD project on a Belgian reform that subsidised first-time hiring, inducing entry by marginal firms yet meanwhile changing the wages they pay. Standard methods addressing selection-into-treatment concepts (like Heckman selection equations and local average treatment effects), or before-after comparisons (including simple DiD or RDD), cannot isolate effects at this shifting margin where treatment defines who is observed. I introduce marginality-weighted estimands that recover causal effects among policy-induced entrants, offering a policy-relevant alternative in settings with endogenous selection. This method can thus be applied widely to understanding the economic impacts of public programmes, especially in fields largely relying on reduced-form causal inference estimation (e.g. labour economics, development economics, health economics).