Red Jahncke offers words of caution at National Review Online for those politicians who want to see universal government-funded preschool in the United States.

Yet another study has found that preschool yields no significant educational benefits. After spending £2 billion annually for almost a decade to fund an expansion of preschool to cover all three-year-olds, the United Kingdom had no lasting improvements in educational achievement to show for it, researchers have found.

In a study published in the current edition of The Economic Journal, the researchers found that “the policy led to small improvements in attainment at age 5,” yet “the effects are short-lived for all groups, becoming essentially zero by age 7.” This finding echoes those of many U.S. studies, which consistently find that any educational gains from preschool fade out over time.

Nevertheless, U.S. preschool advocates from President Obama and presumptive Democratic presidential nominee Hillary Clinton to New York City mayor Bill de Blasio continue to press for the adoption of universal pre-K, or “UPK” in the lingo, as a way to elevate student achievement.

Well, the only thing “universal” about preschool is its failure to produce educational gains. Preschool programs of all shapes and sizes, both in the U.S. and in the U.K., have failed in this goal. Preschool programs do, however, serve an essential function in providing day care so parents can work.