Study after study after study has looked at charter schools run by the Knowledge is Power Program and come to the same conclusion: KIPP schools significantly improve achievement among disadvantaged students.
A new study by researchers at Mathematica Policy Research goes a step further, addressing some of doubts raised by skeptics — specifically the idea that, in the authors’ words, “these improvements reflect advantageous enrollment patterns at KIPP that are not possible at traditional public schools.”
The findings, published in this fall’s edition of Education Next, show KIPP schools attract students who face similar disadvantages to those in surrounding schools, and that their increased achievement cannot be explained by weaker students dropping out or stronger students transferring in.
The researchers looked at 19 of the network’s older middle schools, all of which opened in 2005 or earlier (before KIPP opened its first school in Florida). Using detailed student-level data, they compared the KIPP students to those in the surrounding school districts, as well as a smaller group of nearby middle schools that draw students from the same elementary schools. Then they looked at students who leave the schools and those who transfer into the schools part way through middle school.
We find that, on average, KIPP middle schools admit students who are similar to those in other local schools, and patterns of student attrition are typically no different at KIPP than at nearby public middle schools. In both groups of schools, students who leave before completing middle school are substantially lower-achieving than those who remain. KIPP schools replace fewer of these students in the last two years of middle school, however, and, compared to district schools, KIPP schools tend to replace those who leave with higher-achieving students. Nonetheless, while this difference in replacement patterns is noteworthy, it cannot account for KIPP’s overall impact on student achievement. In particular, the literature on peer effects suggests that KIPP’s student replacement pattern could produce only a small fraction of KIPP’s actual impact on student achievement.
In short, the schools’ positive effects on student achievement hold up even after accounting for student attrition and other “peer effects” examined by the study.
The authors note a potential caveat. While the students who attend KIPP are at least as disadvantaged as those from comparable public schools, they acknowledge there could still be other “unmeasured differences” between the students who attend KIPP and those enrolling in nearby schools. While they look at students’ demographics and their achievement before enrolling, the authors note other factors not directly measured by the study, like “parent characteristics, prior motivation, or student behavior,” could also play a role.
Still, these findings have several implications. For one thing, if certain charter school networks can get results that hold up even after accounting for student enrollment patterns, that should bolster the arguments of people like KIPP Jacksonville board member and state Board of Education Chairman Gary Chartrand, who is looking to attract more high-performing charter groups to Florida’s inner cities.
Also, the researchers themselves point out that if it’s possible for KIPP to achieve these results, its model – from its system for cultivating school leaders to its longer school days and college-going culture – “may include practices that could be effective outside schools of choice.”
“Whether these practices can be replicated in traditional public schools or raise academic achievement across the full range of traditional public-school students remains to be seen,” they write.