Busted Charter Myth #2: Public Charter Schools in Baltimore Do Not Perform Better Than Traditional Schools

There are several versions of this myth, and none of them hold true. Anti-charter advocates have claimed that either public charter schools as a whole under perform compared to traditional schools, or that they under perform for students from historically disadvantaged groups.

The table above shows results for MSA Math Tests in 2014 (2015 PARCC results, while available, are not widely accepted as an accurate measure of student achievement and were not examined). Results for reading and science tests appear at the bottom of this post, and mirrored the results of the math tests: Baltimore Charter Public Schools outperform Baltimore Traditional Public Schools on every measure, across all demographic and economic groups.

Measuring scores for all students in all grades, charter public schools performed better on the test than traditional public schools in Baltimore. 8th Grade students did better in charter schools. 5th Grade students did better in charter schools. Black students and Hispanic students all did better in charter schools. English Language Learner (ELL) students did better in charter schools, and Students With Disabilities (SWD) did better in charter schools. FARMS (Free and Reduced Meals) students did better in charter schools too.

Given that public charter schools serve a student body that is demographically very similar to the district’s student body, this means that the charter school system as a whole has worked very well for Baltimore children. These schools serve students from diverse backgrounds and have improved test scores for all demographic groups.

While there is clearly still an achievement gap within charter schools (reflected in the mean achievement scores for historically disadvantaged groups vs. the scores for all students in the aggregate), the evidence is that public charter schools are eroding the achievement gap within Baltimore’s public schools, not contributing to it.

CLARIFICATION (MAY 3, 2016): The scores are reported for schools in the testing data available here: http://www.baltimorecityschools.org/Page/24385. Average scores reported here are the averages for the public charter schools and for traditional schools. The n value reported in each cell reports the number of schools included in the average.

In some cases, data was redacted by the district to protect the privacy of individual students. All data that was not redacted by the district has been used in this analysis.

If a p value is below .05, the differences between the averages for the two categories are said to be statistically significant.