> The initiative will cost nearly $5 billion through 2019, a hefty sum considering that the state’s current two-year budget for public education is around $15 billion....Project STAR is the gold standard in class-size reduction literature because it’s the only randomized study on the issue that’s been conducted since the early 20th century...Florida’s program cost $20 billion over eight years, about the same as the estimates for the Washington initiative. And Project STAR was estimated to cost about $400,000 for each student who eventually went to college, compared to $133,000 for HeadStart. “Reducing class size is one of the most expensive things you can do in education,” Chingos said.

And people keep asking whether we can afford, ethically or financially, to run randomized trials...