Do KIPP Schools Boost Student Achievement?

KIPP is an expanding network of public charter schools designed to improve educational outcomes among low-income children. The first KIPP schools opened in 1995 and by 2013–2014 there were 141 KIPP schools operating nationally, including 22 schools in California. Prominent elements of KIPP’s educational model include high expectations for student achievement and behavior, and a substantial increase in time in school.

A major challenge in measuring KIPP’s impact is that students choose to attend KIPP schools and may differ from students who have not made that choice. We know, for example, that students entering KIPP middle schools are disproportionately likely to be economically disadvantaged and low achieving prior to enrolling in a KIPP school, but that they are somewhat less likely to have limited English proficiency or to be in need of special education services (relative to other students in their local districts). Accounting for these student characteristics in an article published in Education Finance and Policy, our team at Mathematica Policy Research measured the effect of 41 KIPP middle schools on student achievement over a ten-year period. We used propensity score matching to compare KIPP middle-school students to a matched group of non-KIPP students with similar characteristics and a similar history of elementary-school (pre-KIPP) test scores.

We found that KIPP middle schools had positive impacts on students’ reading and math achievement. Three years after a student entered a KIPP middle school, KIPP boosted achievement on state tests by the equivalent of 90 percent of an extra year of learning in math and two-thirds of a year in reading, on average. These positive impacts were consistent across most KIPP schools in the study, and extended to other outcomes, including performance on science and social studies tests and on a low-stakes test we administered. These results held up when we used schools’ randomized admissions lotteries to estimate impacts experimentally in a subset of KIPP schools. In short, KIPP’s impacts on student achievement are positive, consistent, and substantial.

Whether KIPP’s approach might produce similarly positive impacts if applied in other public schools depends, in part, on exactly what causes the impacts, which remains an open question. Three possible explanations emerge. First, some combination of KIPP features—instructional, philosophical, or logistical—may produce the positive effects. If so, KIPP’s approach might usefully be applied to improve student achievement in many other public schools. Second, KIPP schools may draw students from areas with particularly low-performing traditional public schools. If so, KIPP’s approach might produce positive effects only in communities where existing schools are under-performing.  Third, positive peer effects may contribute to positive impacts. While students entering KIPP had lower test scores than other district students, they may have differed on unmeasured characteristics such as motivation or behavior. If so, then KIPP’s approach would not be likely to produce similar effects when replicated across public schools generally.

KIPP’s effects might be produced by any or all of the above explanations, and further research is needed. By understanding what factors drive the success of KIPP and similar charter networks, we can determine whether and how to scale up their successful practices, either by expanding successful charter networks or encouraging traditional public schools to adopt their practices.

The full study (gated) is in Philip M. Gleason, et al, Do KIPP Schools Boost Student Achievement, Education Finance and Policy, Winter 2014, Vol. 9, No. 1, Pages 36-58.