In the early 90s, when a young economist named Michael Kremer finished his PhD, there had been a few economic studies based on randomized trials. But they were rare. In part because randomized trials – in which you recruit two statistically identical groups, choose one of them to get a treatment, and then compare what happens to each group – are expensive, and they take a lot of time. But then, by chance, Michael had the opportunity to run a randomized trial in Busia, Kenya. He helped a nonprofit test whether the aid they were giving to local schools helped the students. That study paved the way for more randomized trials, and for other economists to use the method. On today's show, how Busia, Kenya, became the place where economists pioneered a more scientific way to study huge problems, from contaminated water to low graduation rates, to HIV transmission. And how that research changed government programs and aid efforts around the world. This episode was produced by James Sneed with help from Willa Rubin. It was engineered by James Willetts. It was fact-checked by Sierra Juarez and Emma Peaslee. It was edited by Molly Messick. Jess Jiang is our acting executive producer. Help support Planet Money and get bonus episodes by subscribing to Planet Money+ in Apple Podcasts or at plus.npr.org/planetmoney. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

It's the thrilling conclusion to our three-part series on AI — the world premiere of the first episode of Planet Money written by AI. In Part 1 of this series, we taught AI how to write an original Planet Money script by feeding it real research and interviews. In Part 2, we used AI to clone the voice of our former colleague Robert Smith. Now, we've put everything together into a 15-minute Planet Money episode. And we've gathered some of our co-hosts to listen along. So, how did the AI do? You'll have to listen to learn what went surprisingly well, where it fell short, and hear reactions from the real-life hosts whose jobs could be at risk of being replaced by the machines. This episode was produced by Emma Peaslee and Willa Rubin. It was engineered by James Willetts and fact-checked by Sierra Juarez. Keith Romer edited this series and Jess Jiang is our acting executive producer. In the radio play, Mary Childs voiced Ethel Kinney; Willa Rubin voiced Alice; and Kenny Malone voiced Dr. Jones and Dial Doom 5000. Help support Planet Money and get bonus episodes by subscribing to Planet Money+ in Apple Podcasts or at plus.npr.org/planetmoney. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy