Pre-Kindergarten Impacts Over Time: An Analysis of KIPP Charter Schools

It’s no secret that high-quality early childhood education can lead to significant and positive short-term impacts for children, particularly those from disadvantaged circumstances. Unfortunately, much of the current research also points to a troubling “fade out” trend—the gains that students make in preschool gradually decrease until they disappear completely.

A recent study from Mathematica seeks to add to this discussion by investigating whether the pre-K programs offered by some KIPP charter schools produce more lasting impacts. Researchers selected KIPP for several reasons, including the fact that it employs several practices that are considered high quality (such as well-educated teachers and low teacher-child ratios). Most significant, though, is that many KIPP pre-K students continue their education in a KIPP elementary school—increasing the probability that their elementary school experience will align with their pre-K experiences, and thereby potentially lead to longer-lasting impacts.

The study explored three research questions and used slightly different methods to examine each. The samples were relatively small, but the analysts were able to employ experimental methods that allow us to draw stronger conclusions about the effects of KIPP pre-K. A series of standardized tests (like the Woodcock-Johnson III Tests of Achievement) were used to measure both academic achievement and executive function (skills that help students do critical things, like focus their attention and multi-task). Interviews of KIPP staff were also conducted. 

First, the study examined the effects of attending a KIPP pre-K and elementary school on student achievement. Specifically, it compared outcomes for students who won KIPP admission via lottery in pre-K and remained in a KIPP elementary school through second grade to the outcomes for students who were not offered admission. Researchers looked at three oversubscribed KIPP elementary schools that offered pre-K in two cities. There were two key findings: First, students who attended both KIPP pre-K and elementary schools made significant gains on reading and math achievement by the end of second grade relative to students who did not win the pre-K lottery. Second, KIPP pre-K and elementary schools may also have had a positive impact on student executive function, though the findings were not statistically significant.

Second, researchers aimed to isolate the effects of KIPP pre-K by comparing outcomes for students who enrolled in a KIPP school starting in pre-K to those who enrolled in KIPP starting in kindergarten. The kindergarten cohort was made up a sample of students from five oversubscribed KIPP schools that did not offer pre-K in four cities. Researchers found that KIPP pre-K may provide an additional benefit for reaching achievement above and beyond just attending KIPP elementary schools. Although the results did not reach conventional levels of statistical significance due to small sample sizes, the researchers found that the magnitude of reading impacts was larger for KIPP schools that offered pre-K than for those that did not, which suggests that “earlier and longer exposure to KIPP improves reading outcomes.”

Third, the study sought to determine how the size of KIPP’s impact changed over time for students who attended KIPP pre-K. To answer this question, researchers examined the impacts for the pre-K cohort in kindergarten and then again in second grade using the same academic tests. The sample was restricted to students who had test outcome data for both kindergarten and second grade. Researchers found that the impact on reading skills persisted over time, but impacts on reading comprehension dissipated by second grade.

Overall, it’s clear that the cumulative impacts of KIPP pre-K and elementary school are positive and substantial—the earlier students are enrolled in a KIPP school, the better. But the biggest takeaway extends beyond the performance of a single charter network. High-quality pre-K is good for kids, but high-quality pre-K plus a great elementary school experience could be the key to avoiding the fade out trend—and that’s why it’s so important that more charter schools be permitted to provide pre-K.

SOURCE: Virginia Knechtel, Thomas Coen, Pia Caronongan, Nickie Fung, Lisbeth Goble, “Pre-Kindergarten Impacts Over Time: An Analysis of KIPP Charter Schools,” Mathematica Policy Research (August 2017). 

Jessica Poiner
Jessica Poiner is an education policy analyst in the Fordham Institute’s Columbus office. She was a 2011 Teach For America corps member who worked and taught in Shelby County Schools and the Achievement School District.