How does scaling up randomised controlled trials make them more effective?

Concerns about the scale at which experiments are conducted have accompanied the wave of randomised controlled trials (RCTs) that have entered the field of development economics. Paul Niehaus discusses why scale is such an important issue and ways researchers can overcome the scepticism about how representative RCTs are for the national populations that policymakers care about.

Randomised controlled trials Large-scale evaluations Research National populations Scaling up Scale Methodology