Replication Data for: The Limits (and Strengths) of Single-Topic Experiments

Abstract: We examine the generalizability of single-topic studies, focusing on how often their confidence intervals capture the typical treatment effect from a larger population of possible studies. We show that the confidence intervals from these single-topic studies capture the typical effect from a population of topics at well below the nominal rate. For a plausible scenario, the confidence interval from a single-topic study might only be half as wide as an interval that captures the typical effect at the nominal rate. We highlight three important conclusions. First, we emphasize that researchers and readers must take care when generalizing the inferences from single-topic studies to a larger population of possible studies. Second, we demonstrate the critical importance of similarity across topics in drawing inferences and encourage researchers to consider designs that explicitly estimate and leverage similarity. Third, we emphasize that, despite their limitations, single-topic experiments have some important advantages.