Students participating in a government preschool program ended up worse off than their peers who did not participate, according to a new study published by Vanderbilt University.

Since 2005, Tennessee has offered full-day prekindergarten for four-year-olds in participating school districts. The study found that students in the program were significantly better prepared for kindergarten. By the end of kindergarten, however, those students were doing just as well as similar students who were not in the pre-K program. By the second grade, students who had been in the preschool program were actually doing worse than the other students. The same was true in the third grade.