Using RCTs to Estimate Long-Run Impacts in Development Economics

We assess evidence from randomized control trials (RCTs) on long-run economic productivity and living standards in poor countries. We first document that several studies estimate large positive long-run impacts, but that relatively few existing RCTs have been evaluated over the long-run. We next present evidence from a systematic survey of existing RCTs, with a focus on cash transfer and child health programs, and show that a meaningful subset can realistically be evaluated for long-run effects. We discuss ways to bridge the gap between the burgeoning number of development RCTs and the limited number that have been followed up to date, including through new panel (longitudinal) data, improved participant tracking methods, alternative research designs, and access to administrative, remote sensing, and cell phone data. We conclude that the rise of development economics RCTs since roughly 2000 provides a novel opportunity to generate high-quality evidence on the long-run drivers of living standards.本研究针对贫困国家长期经济生产率与生活水平相关的随机对照试验（Randomized Control Trials, RCTs）证据展开系统评估。首先，本研究梳理发现，多项研究估算出长期影响显著为正，但目前已有的RCTs中，开展长期评估的案例相对较少。随后，我们通过对现有RCTs开展系统性调研（重点聚焦现金转移支付项目与儿童健康项目），证实其中有相当一部分子集可实际开展长期效应评估。我们进一步探讨了弥合这一差距的可行路径：当前发展经济学领域的RCTs数量呈井喷式增长，但截至目前完成长期追踪的研究数量却十分有限。可行的解决方案包括构建新的面板（纵向）数据、优化研究对象追踪方法、采用替代研究设计，以及获取行政记录、遥感与手机数据等资源。最后我们得出结论：自2000年左右兴起的发展经济学RCTs研究，为获取关于生活水平长期驱动因素的高质量证据提供了全新契机。