There is a lot of noise around the evaluation of charter schools, and a paucity of good data, which makes most comparisons of little use.  That is starting to change.

One of the problems in gauging the effectiveness of charters is the comparative group.  Charters are generally open-lottery admissions; critics claim that their students self-select, advocates believe that the schools do a better job educating kids.  The best way to test that theory would be to compare the students who applied and were randomly accepted with a group who applied and did not get in. There is no self-selection among applicants.

In NYC, a comprehensive eight-year study by Stanford professor Caroline Hoxby was just released. Here is an editorial from the NY Daily News:

It’s official. From this day forward, those who battle New York‘s charter school movement stand conclusively on notice that they are fighting to block thousands of children from getting superior educations.

An exhaustive, eight-year-long study has documented that kids in the city’s charter schools have outachieved students at traditional public schools by an enormous margin.

Grade by grade, charter students climbed further up the skills ladder, so that by eighth grade they scored 31 points higher than their peers on math exams and 23 points higher on English tests.

What do those numbers show? They show that the charter children, most of whom are from poor and minority-group families, had gotten almost 90% of the way toward closing the divide in math scores between Harlem kids and those in Scarsdale, as well as two-thirds of the way in closing the gap in English.

Here is the coverage from the NY Times.

Charter advocates need to take an important lesson away from this study as well: NYC has an effective and rigorous authorizing process (as I would argue Denver does as well, even if other Colorado districts do not).  I don’t know much about NYC’s track record for closing underperforming charters, but my guess is that they have shown a willingness to do so, and a good authorizer will act to close charters when appropriate.

And obviously, merely starting a school under a designation of “charter” is not enough.  As public schools, charters depend upon an effective and functioning local authorizer — usually the school board — who is able to select the best models to fit the individual needs of each district.

This is a different activity for many districts, who often struggle with the important change of shifting their focus from acting solely as a monopoly school operator to also managing an array of independent organizations that run schools and provide services.

The NYC study shows the benefits of districts that can accept and manage this transition.