Greg Toppo:

An ambitious public pre-kindergarten program in Oklahoma boosts kids’ skills dramatically, a long-awaited study finds, for the first time offering across-the-board evidence that universal preschool, open to all children, benefits both low-income and middle-class kids.
The large-scale study, by researchers from Georgetown University’s Public Policy Institute and Center for Research on Children in the United States, looked at the skills of about 3,500 incoming kindergartners in Tulsa, where state-funded pre-kindergarten has been in place for 18 years — and offered universally for nearly a decade.
The researchers found that as the kids entered kindergarten those enrolled in the state program had better reading, math and writing skills than kids who were either not enrolled in preschool or who spent time in the federally funded Head Start program.
Previous research has shown that high-quality preschool pays off in better skills, especially for low-income kids. But until today’s findings, even the biggest studies stopped short of making the case that universal programs, with children from all backgrounds, benefit virtually all of them.

National Institute for Early Education Research.