How much evidence is enough before we know that a global development intervention works for people? How much evidence is enough to know that a program is worth scaling to millions of people because it works and benefits lives across multiple settings and contexts?
These are great questions that Michael Hobbes raises in an article in the most recent issue of The New Republic. In fact, we at Evidence Action think a lot about this. Our mission is to scale programs that have been proven to work so they benefit millions of people.
Unfortunately, Mr. Hobbes used a poor example to raise these questions by focusing on deworming. In the case of mass deworming of children and our Deworm the World Initiative, the policy has followed the (rigorous) evidence. Deworming has a well-proven, clear causal chain from intervention to effect.