Unpacking Treatment Effect Heterogeneity in a Large-Scale Dropout-Prevention Experiment
NBER Working Papers · 2026 · Thomas Dee、Chloe R. Gibbs、Rebecca Margolit-Chan、Lillian Morrell、James X. Sullivan
中文摘要
按时完成高中学业，是顺利过渡到中学后教育和劳动力市场的关键一步。本项随机对照试验在两个城市弱势学区开展，以异常大的规模（n=2,528）检验一项成熟、综合的学生支持项目的有效性。尽管该项目对毕业率的总体影响较小且统计不显著，但探索性分析显示，不同实施地点和不同时期的效应存在显著差异，这与处理时点和项目实施方面的异质性相呼应。这些发现凸显了扩大干预规模所面临的挑战，并引发了对将小规模、单一地点评估结果推广至其他情境的担忧。
Abstract
Timely high school completion is a critical step in successful transitions to post-secondary schooling and the labor market. This randomized controlled trial, deployed in two urban, disadvantaged school districts, tests the effectiveness of a mature and comprehensive student-support program on an unusually large scale (n=2,528). While overall effects on graduation rates are small and statistically insignificant, exploratory analyses reveal notable variation by site and over time, mirroring heterogeneity in treatment timing and program implementation. These findings highlight the challenges of scaling interventions and raise concerns about generalizing results from small-scale, single-site evaluations.