There is a strong and politically bipartisan push to increase access to government-funded pre-K. This is based on a premise that free and available pre-K is the surest way to provide the opportunity for all children to succeed in school and life, and that it has predictable and cost-effective positive impacts on children’s academic success.
The evidence to support this predicate is weak. There is only one randomized trial of a scaled-up state pre-K program with follow-up into elementary school. Rather than providing an academic boost to its participants as expected by pre-K advocates, achievement favored the control group by 2nd and 3rd grade. It is, however, only one study of one state program at one point in time. Do the findings generalize? The present study provides new correlational analyses that are relevant to the possible impact of state pre-K on later academic achievement. Findings include:
no association between states’ federally reported scores on the fourth grade National Assessment of Educational Progress (NAEP) in various years and differences among states in levels of enrollment in their state’s pre-K program five years earlier than each of those years (when the fourth-graders taking NAEP would have been preschoolers);
positive associations (small and typically not statistically significant) between NAEP scores and earlier pre-K enrollment, when the previous analysis is conducted using NAEP scores that are statistically adjusted to account for differences between the states in the demographic characteristics of students taking NAEP; and
no association between differences among states in their gains in state pre-K enrollment and their gains in adjusted NAEP scores.
Under the most favorable scenario for state pre-K that can be constructed from these data, increasing pre-K enrollment by 10 percent would raise a state’s adjusted NAEP scores by a little less than one point five years later and have no influence on the unadjusted NAEP scores.