Relatively few rigorous studies of the effectiveness of contemporary public prekindergarten programs have been conducted despite the growing number of programs and large monetary investments they require. The study on which this presentation is based was launched in collaboration with the Tennessee State Department of Education to provide an assessment of the effects of the statewide Tennessee Voluntary Prekindergarten (TN-VPK) program on the economically disadvantaged population it serves. Across two cohorts, 80 different schools in 29 Tennessee school districts with more applicants than they could accommodate submitted applicant lists from which 3171 children were randomly assigned to participate or not participate in TN-VPK. Of those, 1077 consented children (773 TN-VPK; 304 nonparticipants) have been individually assessed at the beginning and end of pre-k, end of kindergarten, and end of first grade in an intensive substudy.

The children who participated in TN-VPK attended an average of 149 days during the school year while more than half of the children who were not admitted to TN-VPK stayed home and 27% enrolled in Head Start or private center-based childcare. During the course of the pre-k school year, the academic skills of all the children in the intensive substudy improved on Woodcock Johnson III measures of literacy, language, and math skills. However, the children who participated in TN-VPK gained significantly more on all these measures than the children who did not attend with effect sizes ranging from .12 to .46. Positive effects of TN-VPK were also found on the kindergarten teachers’ ratings of children’s preparedness for kindergarten and their ratings of the children’s classroom work behavior and social behavior. In addition there were larger effects on the academic skills of children who were not native English speakers than for those who were. Follow-up assessments at the end of kindergarten and the end of first grade for the TN-VPK group, however, showed that most of these effects were not sustained. On the other hand, there are some indications of better outcomes emerging for the TN-VPK group on grade retention. Discussion of these results will focus on the difference between short-term effects on cognitive skills and long-term effects on school engagement and hypotheses about why some pre-k effects may not be sustained and others may emerge well after the end of prekindergarten. Meanwhile, the study continues and will follow the participating children through at least third grade.