Lobbyists for pre-K always cite the Perry Preschool Project, conducted 50 years ago in Ypsilanti, Michigan, as their model. But that project was prohibitively expensive -- about $19,000 a year per student in today's dollars. The kids were put in separate classes of only six preschool children, each class taught by a well-trained teacher with a bachelor's degree in early childhood education plus extra training in a special curriculum. Each teacher then had a 90-minute visit at each child's home in the afternoon. We've just found out that the Perry Project had another unusual feature that was not revealed before and makes it very different from the usual government daycare. All the 123 kids in the Perry Project had stay-at-home moms, so we wonder why they needed daycare in the first place.
When we look at any scientific experiment to see if it is valid, the essential requirement is that others can imitate it and get the same results. But the Perry Project has never been replicated in the 50 years since it took place in Michigan, despite many subsequent attempts, so the Perry study is not scientifically credible.
Listen to the radio commentary here: