Successfully Scaled Solutions Need Not be Homogenous

Al-Ubaydli et al (2020) point out that many research findings experience a reduction in magnitude of treatment effects when scaled, and make a number of proposals to improve the scalability of pilot project findings. While we agree that scalability is important for policy relevance, we argue that non-scalability does not always render a research finding useless in practice. Three practices – a) ensuring that the intervention is appropriate for the context, b) that heterogeneity in treatment effects are understood, and c) that the temptation to try multiple interventions simultaneously is avoided can allow us to customize successful policy prescriptions to specific real-world settings