No “teacher effectiveness gap” in NYC

The “teacher effectiveness gap” was just a myth, writes Mike Petrilli, citing the New York City teacher ratings published this weekend. Fourth- through eighth-grade teachers rated highly effective and very ineffective “are evenly distributed  around New York City in low-poverty and high-poverty schools, he writes.

Some teachers in poor, low-performing schools earned high value-added ratings because their students improved on past peformance, even though they didn’t catch up with advantaged students. And some teachers with easy-to-teach students earned low ratings because their students didn’t maintain their previous performance levels.


Affluent schools are spending more for their teachers — but they aren’t getting better results. We know from research by Marguerite Roza and others that low-poverty schools tend to employ older, and thus more expensive, teachers than their poorer counterparts. . . . But these older, more expensive teachers aren’t getting stronger value-added gains than their younger, less expensive peers.

It’s also possible that educators and parents in affluent, high-achieving schools don’t think raising math and reading scores is a high priority, he concedes. Perhaps these schools are spending more time on “art, music, science, history and P.E.” That’s a reasonable choice.

Shipping teachers from low-poverty to high-poverty schools, as many propose, would be “misguided,” concludes Petrilli.

The very large margins of error in evaluating individual teachers are troubling. Value-added numbers over five years, available for some teachers, would be meaningful, but a single year’s data that places a teacher somewhere between the 30th and the 90th percentile . . . That’s useless.

There’s no way out of the evaluation trap, complains Arthur Goldstein, a high school teacher who specializes in teaching English to immigrants.

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