Skeptics of charter schools have argued that the impact of charters on student performance can be attributed to their ability to “skim motivated students.” That is to say, in simplified terms: high-flying charters are high-flying, not because of their ability to educate kids more effectively than their traditional public school peers, but because of their ability to attract and retain cream-of-the-crop students.
Mathematica Policy Research, a top-notch policy and program evaluator, has recently looked into this precise question, using KIPP charter schools as its guinea-pig. KIPP, with its 125 schools in 39 states and the District of Columbia, is one of the largest charter school networks in the U.S. In Ohio, it operates one middle school in Columbus (sponsored by Fordham).
The researcher ask whether KIPP schools have (1) higher rates of attrition of its low-performers, compared to their district school peers; and (2) whether KIPP schools have higher rates of “late arriving” high-performers, compared to their district counterparts. If the researchers find higher rates of attrition or late-arriving, one could infer that the positive impact that KIPP charters have on student performance (found here, here, and here) is a function of selection and (de-selection) of students rather than of KIPP’s educational approach.
When the researchers compared attrition rates, they found no significant difference. KIPP schools lost students of the same quality, at the same rate as their district counterparts; in fact, both tended to lose mostly low-achievers. So with respect to attrition: check, one cannot attribute KIPP’s positive impact to its ability to “lose” or “de-select” lousy students. When the researchers compared late arrivals, KIPP schools did attract a higher proportion of high-achieving students than did district schools. So the evidence is less clear: some of KIPP’s positive impact might be attributable to the late-arrival of smart youngsters.
The researchers conclude that, despite KIPP’s higher rate of late-arriving, high-performers, one cannot attribute KIPP’s “large cumulative impacts on student achievement” to this factor alone. (This would be mediated through “peer effects.” Think about it like this: studying with more “smart” people should make one smarter.) The bottom-line, then: in light of rigorous evaluation, KIPP continues to shine. The research here indicates to even the severest skeptic that KIPP’s educational approach—no excuses, more time, etc.—has a measurable, positive impact on student learning.
SOURCE: Ira Nicholas-Barrer, Brian P. Gill, Phillip Gleason, and Christina Clark Tuttle, Student Selection, Attrition, and Replacement in KIPP Middle Schools, (Washington D.C.: Mathematica Policy Research, September 2012).