In the late 1990s, Boston expanded its public pre-K program, but it did not have nearly enough spots for every 4-year-old in the city. So it used a lottery to help determine which children could enroll.
That lottery created an opportunity for academic researchers. It meant that thousands of otherwise similar children would have different life experiences based on random chance. And random chance is a powerful way for social scientists to study cause and effect. It may be the closest thing to a laboratory experiment in the real world.
Pre-K was a particularly good subject to study, because there has been a long-running debate about how much it matters. In the 1960s and ’70s, studies of two small preschool programs — known as the Perry and Abecedarian programs — showed major benefits for the children who attended them. But some experts pointed out the two programs were of a higher quality than most pre-K programs. For that reason, a community that enacted universal pre-K could not expect to replicate the benefits of Perry and Abecedarian.
The evidence about larger pre-K programs — like the federal Head Start program — was more mixed. Graduates of Head Start seemed to do better on math and reading tests during the early years of elementary school. As they got older, though, the positive effects often faded, leaving the value of universal pre-K unclear.
calling for the federal government to subsidize state pre-K programs. About two-thirds of 4-year-olds and half of 3-year-olds now attend such programs. Biden wants to make them universally available, at an additional cost of about $20 billion a year (or less than 1/30th of what the federal government spends on Medicare). He would pay for it by raising taxes on the wealthy.
In today’s newsletter, I want to tell you about the results from the Boston pre-K study. They are being released this morning by three economists, from the University of Chicago, the Massachusetts Institute of Technology and the University of California, Berkeley.
mixed evidence on Head Start.
But test scores are mostly a means, not an end. More important than the scores are concrete measures of a student’s well-being. And by those measures, the students who won the lottery fared substantially better than those who lost it.