A host of other large studies using data on thousands of children shows the same pattern of ineffectiveness, fadeout, and/or harm. The most recent is a multi-year controlled study from Tennessee, Senator Alexander's home state, about which Education Week reported the following conclusions:
". . . Children started off school strong, but by kindergarten were generally indistinguishable academically from comparable peers who did not enroll in the program" and "by 3rd grade the children who attended pre-K were performing worse on some academic and behavioral measures than similar classmates who were never in the program."
Even results from the one study that purports to show long-term benefit are still described as "dismal" in the mainstream press. There is simply no persuasive research to countervail this massive evidence.
But politicians and the education establishment cling to the concept of preschool. Advocates of Common Core and other progressive-education philosophies want to extend government tentacles to ensnare ever younger children. The managed economy and managed society can be achieved more quickly if toddlers are removed from their homes and herded into government preschool, where the uncontrolled influences of parents, families, and religion can be replaced with others more likely to advance government goals.
What should be done instead? Perhaps listen to researchers such as Dr. William Jeynes of UC-Santa Barbara, who identified three of several important factors that significantly improve the performance of minority students relative to white students (closing the "achievement gap"): intact families and religious faith, phonics instruction, and real parental involvement. Having government go even further to replace parents doesn't work and will never work.
If politicians -- including presidential candidates -- are serious about improving education, they'll reject the empty promises of invasive, ineffective, harmful, federal preschool programs. Instead they'll listen to parents who innately understand that their children will develop better in the care of people who love them than with the government. The candidate who leads this fight against relentless government "solutions" in education will reap the political benefits.