BOULDER, CO (May 9, 2017) – In recent years, the nation has seen a debate regarding the effectiveness of charter schools and their impact on the larger school systems in which they operate. A recent Manhattan Institute report explores the question of whether or to what extent the performance of New York City (NYC) charter schools is explained by “cream-skimming,” or drawing a group of students from public schools who are disproportionately motivated and academically accomplished.

New York Charter Schools Outperform Traditional Selective Public Schools: More Evidence that Cream-Skimming is Not Driving Charters’ Success was reviewed by Sarah A. Cordes of Temple University.

The report compares the performance of NYC’s charter middle schools with a set of selective but non-charter public middle schools. Unlike most public schools, these NYC schools consider students’ prior performance before admitting them and therefore make an interesting comparison group for charters.

Findings presented in the report suggest that, controlling for student characteristics, charter schools perform no differently in English Language Arts and significantly better in math than the selective schools. Based on this, the report concludes that the performance of NYC charter schools cannot be explained by cream-skimming.

While on its face this conclusion may seem logical, Professor Cordes notes that the report suffers from two primary flaws. First, it assumes that selective school applicants are higher performing and more motivated than charter school applicants. This is an unfounded assumption because all students are required to apply to traditional middle schools in NYC, while applying to a charter school requires navigating an additional application process. Second, the report relies on a single year of data to make comparisons of inappropriate outcomes that do not capture individual student growth—an approach that does not address either the question of cream-skimming or charter school success.

Accordingly, as an examination of cream-skimming in charter schools, this report misses the mark. Professor Cordes writes, “Addressing the question of cream-skimming in NYC charter schools will require the use of longitudinal student-level data and much more rigorous methods.”

Find the review by Sarah A. Cordes at:
http://nepc.colorado.edu/thinktank/review-nyc-charters

Find New York Charter Schools Outperform Traditional Selective Public Schools: More Evidence that Cream-Skimming is Not Driving Charters’ Success, by Marcus A. Winters, published by the Manhattan Institute, at:
https://www.manhattan-institute.org/sites/default/files/R-MW-0317.pdf