Lots of government and charity programmes aim to improve education, health, unemployment and so on. How many of these efforts work?

The vast majority of social programs and services have not yet been rigorously evaluated, and…of those that have been rigorously evaluated, most (perhaps 75% or more), including those backed by expert opinion and less-rigorous studies, turn out to produce small or no effects, and, in some cases negative effects.

This estimate was made by David Anderson in 2008 on GiveWell’s blog. At that time, he was Assistant Director of the Coalition for Evidence-Based Policy.

This has become a widely-quoted estimate, especially in the effective altruism community, and often gets simplified to “most social programmes don’t work”. But the estimate is almost ten years old, so we decided to investigate further. We spoke to Anderson again, as well as Eva Vivalt, the founder of AidGrade, and Danielle Mason, the Head of Research at the Education Endowment Foundation.

We concluded that the original estimate is reasonable, but that there are many important complications. It seems misleading to say that “most social programmes don’t work” without further clarification, but it’s true that by focusing on evidence-based methods you can have a significantly greater impact.