We examine the generalizability of internally valid estimates of causal effects in a fixed population over time when that population is subject to aggregate shocks. This temporal external validity is shown to depend upon the distribution of the aggregate shocks and the interaction between these...

We study the impact of cognitive behavioral therapy (CBT) for individuals selected from the general population of poor households in rural Ghana. Results from 2-3 months after a randomized intervention show strong impacts on mental and physical health, cognitive and socioemotional skills, and...

Do non-traditional digital trace data and traditional survey data yield similar estimates of the impact of a cash transfer program? In a randomized controlled trial of Togo's COVID-19 Novissi program, endline survey data indicate positive treatment effects on beneficiary food security, mental...

Many basic economic theories with perfectly functioning markets do not predict the existence of the vast number of microenterprises readily observed across the world. We put forward a model that illuminates why financial and managerial capital constraints may impede experimentation, and thus...