Sunday, February 26, 2012

P.S. 234 -- It's no Lake Wobegon

Garrison Keillor
I rarely take statistics seriously when it comes to teacher evaluation. Especially when they're based on student test scores and published in the New York Times. But this one is too good to pass up.
At Public School 234 in TriBeCa, where children routinely alight for school from luxury cars, roughly one-third of the teachers’ ratings were above average, one-third average and one-third below average.
I mean, except in Lake Wobegon, isn't this what average means (no pun intended)? It's the perfect distribution. If you fired the bottom third, wouldn't one-third still be below average?

The Times story continues:
At Public School 87 on the Upper West Side, where waiting lists for kindergarten spots stretch to stomach-turning lengths, just over half the ratings were above average. The other half were average or below average on measure, based on student test scores.
Amazing! Half above and half below average. How do they do it?

If this trend continues, we can only assume that in New York City (and in the universe as a whole), half the teachers will be above average and half below. And if these ratings are based on test scores, that must hold true for students as well. 


  1. I think the corporate reform movement and the corporate politicians have spent a lot of energy demonizing teachers and public schools so that the public will believe these kinds of random stats that show 1/3 of the teachers coming up "ineffective" every year and be on board with firing lots of teachers every year.

    The problem for the corporate reformers is this: when they were doing this to teachers who teach in schools in areas that are populated by low income parents, people of color, etc. they were able to get away with it. But now that they are targeting teachers in an affluent area like TriBeCa (and soon Scarsdale, Great Neck and the like when the Cuomo/Tisch/King/Mulgrew/Iannuzzi evaluation system goes statewide), they are going to get pushback from politically active, affluent people.

    They could ignore the complaints and protests coming from the powerless, but they are not going to be able to ignore the complaints coming from parents in TriBeCa, Park Slope, Scarsdale and Great Neck.

    It's a shame that's what it takes, but unfortunately, that's what it takes.

    It is good to see that parents at that school in the Times story GOT that these scores do not correlate to teacher quality. That kind of evidence, coupled with the kind of data-based analysis Gary Rubenstein is doing on the VAM, may still bring down this value-added house of cards.

    We'll see.

    The corporate media and pols are doing a hefty lifting job in this battle, so the odds are still as stacked as the VAM algorithms.

    That said, the publication of the TDR's has moved some of the conversation to the tests and the VAM, and that is a good thing.

    No wonder Merry Merryl Tisch was so worried that the TDR publication might jeopardize the new teacher evaluation system.

  2. Today, the Daily News, Post and other N.Y. media published names and pictures of the city's "worst teacher(s)." Disgusting. Even worse is the fact that Arne Duncan has backed such publication.


Agree? Disagree? Let me hear from you.