In 600 B.C., Daniel of Judah had a problem. Babylonian King Nebuchadnezzar was forcing the Israelites to eat only meat and wine. Daniel thought the Israelites would be healthier on a diet of water and vegetables. With the king’s blessing, for ten days a group of Israelite children ate vegetables while another group of children dined on meat. The two groups of children were compared, the Israelite children looked healthier, and the clinical trial was born.

The same technique is used today to test pharmaceuticals: a new pill is tested against a placebo in randomized controlled trials. But social innovators around the world are now employing clinical trials as part of a growing movement to bring new, rigorous scrutiny to the results of their efforts, whether it is improving the environment, education or the lives of the poor.

Clinical trials are only one example in a trend. Organizations dedicated to doing social good are increasingly employing a raft of new efforts to monitor the impact of their activities. Social innovation is shifting toward nimble, adaptable design techniques and meticulous efforts to gauge success and failure. Welcome to the new science of measuring impact.