Environmental law relies on self-monitoring by regulated parties, but reporting violations persist in nontrivial numbers. Failure to report on time can mask pollution problems and impede efficient enforcement efforts. We examine correlates of late reporting and present results of a collaborative field experiment that involved sending over 24,000 customized emails from U.S. EPA to randomly selected permittees. Our results are threefold. First, before the intervention, late submissions were associated with facilities facing less scrutiny (minor and general permittees) and the mining industry. Second, reminders reduced late submissions by 10-20% on average. Third, causal forest analysis reveals heterogeneous treatment effects: permittees in rural areas and with a prior late submission history responded more positively, while permittees in densely populated areas, in the mining industry, or publicly owned treatment works appear less responsive. These results indicate where low-cost, customized reminders can help most while informing for whom stronger interventions may be required.
Regulation, Evaluation, and Governance Lab