Full-Day Kindergarten Produces More Learning Gains, Study Says

Pupils make equivalent of one month’s progress with longer school days.

A new national study provides some of the strongest evidence to date to support what many educators and parents of young children already believe: Children learn more in full-day kindergarten programs than they do in half-day programs.

The findings, scheduled to be published in the February issue of the American Journal of Education, are based on federal data from a nationally representative sample of 8,000 children in public kindergarten programs. The results show that, on average, the learning gains that pupils make in full-day programs translate to about a month of additional schooling over the course of a school year.

“If full-day kindergarten really does show these large effects, the question we have is why doesn’t every school in America offer full-day kindergarten?” said Valerie E. Lee, a lead author of the study and an education professor at the University of...