In 2009, Congress spent $3 billion on “School Improvement Grants” for the worst-performing schools in the country. As far as we can tell, those grants did nothing. Universities that hired a Chief Diversity Officer between 2001 and 2019 did not end up with more diverse students, faculties, or administrators. The American government spent $280 million to help Afghan women get jobs, and now they can’t really say whether any women got any jobs.1 Remember 20 years ago, when giving laptops to kids in developing countries seemed like the most important thing to do? Well, a 10-year RCT of 531 rural schools in Peru found zero effects of “One Laptop Per Child” on academic performance.2 Researchers developed four different messages that were supposed to convince parents to vaccinate their kids. None of the messages worked, and one of them accidentally made parents more likely to believe that vaccines cause autism.