New charter rankings answer some questions, raise others

Not all public charter schools are equal, something we know already, but new rankings confirm that. On December 6, the D.C. Public Charter School Board released a rating system that shows a portion of outstanding schools and another share below par, with the rest falling somewhere in the middle. The ratings put charters into three tiers, based on a number of common metrics. They evaluate schools on student achievement and academic growth on standardized tests (compared to students in public schools), as well as attendance and enrollment. The ratings have implications for continued monitoring by the public charter school board, and, of course, for parents who are making choices about where to send their children.

How did D.C.’s public charters fare? Almost a third (22 schools) were in the top tier, 34 schools were in the second tier and 15 in the bottom.

Not all of the information contained in the rankings is new--DC CAS scores play a significant part of the rankings. But the snapshots are a substantial improvement, offering a detailed, easy-to-read examination of individual schools and the D.C. public charter system as a whole. This is critical in a city where nearly 40% of public school students attend a public charter, according to last year’s audited enrollment. (Preliminary unaudited data from this school year indicate that charter enrollment continued to climb, with a 9% growth over the past year.)
A quick review of the rankings of standard charter schools also reveals that:

•    The highest share of the top tier schools are in Wards 1 and 4.
•    Ward 5 has the highest share of charters (nearly 25% of all charters are there), and it has the highest percentage of the bottom tier charters.
•    Wards 7 and 8 also have a large share of charter schools, but also some of the worst performing schools.

While the ratings answer some questions, particularly around comparability, they raise other questions (including about the rating scheme itself). We mention a few of them below.

For “standard” charters. DC CAS performance makes up 80% of a school’s score. That makes sense, since it’s hard to measure things like teaching quality and CAS performance is a common metric, but it is not a complete school quality measure. To its credit, the system looks at student growth on the CAS as well as proficiency. This gives a better sense of whether a school is moving students up, compared to their peers with similar initial scores. (The student growth model—which is a larger topic than can fit in this blog—is explained in detail on the PCS board website.)

Also, scores for top tier schools range widely. A total of 100 points is possible in the scoring system, and a school could make it into Tier 1 with a score of 65 points or higher. The charters in the top tier range from a low score of 67% to high score of 92%. The range for middle tier schools was 35-64%.

Any rating system has its limitations. But, overall, this performance report brings bring more clarity, comparability and accountability to the many public charters. The school snapshots provide a detailed picture of school achievement, but they also deserve a careful look behind the ratings.

The Washington Post reports that similar rankings are expected soon from DCPS and the Office of the State Superintendent of Education, which should allow greater comparability between schools in the public system and public charter system.