The National Alliance of Public Charter Schools just released some national market share data.

List of Cities with Highest Charter Market Share

Some quick thoughts:

1. All top three market share cities have charter sectors with positive effect sizes: CREDO has found statistically positive and significant effects in New Orleans, Washington D.C., and Detroit.

2. Most cities have not been rigorously studied: Outside of Indianapolis (positive effects), I couldn’t find rigorous research on any other markets. Someone should pay CREDO to do this.

3. Non-reform, Midwestern: About 50% of the high-market share cities listed are in the Midwest – and most of these cities are not reform hotspots, at least in terms of the national narrative.

4. Diversity in size: District size varies from 13,000 to 200,000. I’ve always believed that charters can scale in large markets, and this data, at the very least, shows that it’s possible.

List of Cities with Highest Absolute Charter Enrollment

Some quick thoughts:

1. Most cities that have been studied show positive effects: Los Angeles, New York, Detroit, New Orleans, and Washington D.C., all show positive effects. Chicago shows neutral effects. To my knowledge, none of the other cities have been rigorously studied. This should happen!

2. These cities serve about 25% of total charter enrollment: The top ten enrollment cities serve about 600,000 of a little over 2 million charter students.

In Sum

I want to mull this over more, but I’d say the above data gives me mixed emotions.

On one hand, we clearly see that many of the top charter markets are achieving significant and positive effects.

On the other hand, there appear to be very few cities where charter growth is leading to transformational systems level change, both because of low market share penetration and varying charter sector quality.

If you wanted evidence that charter schools are not a ticket to educational nirvana, this is it.

If you wanted evidence that charter schools can push large educational systems in statistically significant and positive direction, you can find that here too.

If you wanted a lot of rigorous research on a bunch of cities, unfortunately, that’s nowhere to be found.

Addendum: Ask and Ye Shall Receive 

CREDO just today released Ohio study. Overall, mixed and mediocre. But Cleveland statistically significant and positive for black children in poverty and Dayton statistically positive and significant for reading for students in poverty.