Vanderbilt University has a longitudinal study of the effects of such a program on children’s academic success through the 6th grade.
Researchers at Vanderbilt University have been running a long-term study on Tennessee’s state pre-K program, following 2,990 low-income children. The program was oversubscribed, so researchers followed applicants who ended up in a program versus those who were turned away. This means all the children had parents motivated to sign them up for pre-K, which makes for a statistically appropriate control group.
The researchers found, in sum,
[C]hildren randomly assigned to attend pre-K had lower state achievement test scores in third through sixth grades than control children, with the strongest negative effects in sixth grade.
A negative effect was also found for disciplinary infractions, attendance, and receipt of special education services, with null effects on retention.
In a spate of academic integrity, the researchers also wrote,
…no distinctive characteristics of the Tennessee program have yet been identified that are a likely explanation for the disappointing findings.
The Wall Street Journal offered one possible explanation:
One theory worth a hearing is that these programs expose children to more rigid academic settings before it is developmentally appropriate.
I offer another possibility, one that is not at odds with the WSJ‘s. It may be that the parents of children who got into the Pre-K program, thinking their children’s future is secured, relaxed their close and constant oversight of their children’s schooling, performance, execution of homework, and so on relative to that of the parents whose children didn’t get in. That parental oversight and supervision also is a Critical Item in children’s academic performance, especially in those first years of school.
Either possibility, especially in combination with the study’s outcome, suggests that, particularly from the Federal level, government funding of grade school programs is at best a waste of taxpayer money.
The study itself can be found behind this paywall.