Walking the talk: the need for a trial registry for development interventions

Recent advances in the use of randomised control trials to evaluate the effect of development interventions promise to enhance our knowledge of what works and why. A core argument supporting randomised studies is the claim that they have high internal validity. The authors argue that this claim is weak as long as a trial registry of development interventions is not in place. Without a trial registry, the possibilities for data mining, created by analyses of multiple outcomes and subgroups, undermine internal validity. Drawing on experience from evidence-based medicine and recent examples from microfinance, they argue that a trial registry would also enhance external validity and foster innovative research.