Cherry picking in New York

New York’s Gov.-elect Elliot Spitzer wants to lift the cap of 100 charter schools in the state. The state teachers’ union (NYSUT) wants to keep the lid on. So the union released a study showing most charters perform no better than district-run public schools. But the study didn’t compare charters to all schools in the district with similar demographics: The union cherry-picked the highest scoring non-charter, writes Peter Murphy in a New York Post column:

It rigged its study by comparing each charter school against a single, cherry-picked district school. Yes, the rates of student poverty were similar, but NYSUT ignored the many other district schools that performed below those same charter schools.

In other words, the study does not show that most charters are no better on average than regular public schools, but simply that most districts with a charter have at least one “traditional school” that’s at least as good as the charter.

Via Joe Williams of Chalkboard, who blogs about it here and here. He adds, thanks to Alert Reader, that the union study compared Bronx Prep Charter School, which takes all comers through a lottery, with Mott Hall, which has “selective admissions standards, i.e. you’ve got to test/interview well in order to even have a chance at getting in.”

Using NYSUT’s “bizarre methodology,” Joe finds unionized charter schools do worse than non-union charters.

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  1. while I’m not surprised at the tactic (and our local charter outperformed ALL district schools) I do have to ask if the author, Peter Murphy, is a regular columnist … I read it as an op-ed piece since his title was “director of policy for the New York Charter Schools Association”. Joanne, you know the newspaper industry, inside and out: are they different classes of authors?

  2. I’m pretty sure Murphy isn’t a regular columnist. Newspapers often run columns from non-staffers who have special knowledge or interest in an issue. I’ll change the ID.