Friday, February 25, 2011

When Tautology Takes Hold

Richard Whitmire:

– The heart of the book lies in trying to explain why low income black children in D.C. are as much as two years behind similar children in several other urban areas. My conclusion, from visiting successful and unsuccessful schools in mirror neighborhoods, was that the schools making progress were those with forceful new leaders who replaced some, or even all, of their teaching staff. That lined up with what experts on D.C. schools advised me from the beginning: when Rhee arrived in D.C. in 2007, only about a third of the teachers were capable of making significant progress with their students.

To Kahlenberg: If teacher quality wasn’t the main player behind D.C.’s lapses, what was? Money spent per pupil there certainly wasn’t a player. ...

– Of course poverty and segregation matter. A lot. And don’t forget what usually gets blamed by both D.C. teachers and parents – bad parenting. Again, though, you have to explain why D.C. kids are behind kids just like them in other cities. Are D.C. parents really that much worse at parenting? Doubtful.

By the same token, what evidence is there that D.C. teachers are that much worse at teaching? In particular Whitmire is trying to make an apples to apples comparison to other urban US school districts.

Would a study of Philadelphia classroom practices compared to DCPS practices reveal the teacher quality source of a 14 point (or nearly 1.5 years if you insist on mangling the data) difference in 8th grade NAEP scores (in favor of Philly)? If Detroit and DC exchanged teaching forces would DC's eighth graders lose a year of math and Detroit's gain one? Why does Baltimore have higher teacher quality (a whole semester's worth!) than DC?

I see no reason to think DCPS's teaching force is uniquely low quality, but as a city Washington DC is clearly unique in many ways, most of which are not conducive to high test scores.

Do you think Boston would score as high if it wasn't part of Massachusetts?

Would Charlotte-Mecklenburg County score as high if it wasn't a county eight times larger than DC geographically, with twice the population and half the poverty rate? What if you just take the poorest quarter of Charlotte and segregate its students? Would teacher quality render that moot?

Washington DC has the third highest income inequality of any city in the US, a large private school sector for the wealthy, and at least some tendency toward higher transience among higher-income earners, thus less personal investment in long-term community resources like public schools.

Also, this may make me sound ignorant, I have no idea why poor people ever moved to Washington DC in the first place. I know why poor people moved to Detroit, or Pittsburgh, or Boston, or even Baltimore, but as far as I know there was never any industry in DC. So yes, I can see that there was a natural tendency to use education and other public works as employment programs, but we don't know the counterfactual. How else was this supposed to play out?

So yes, you can look at all this and say "See, that's what I mean, because of all of the above and more, DC has low teacher quality, which is exactly what I'm saying." But it doesn't answer the question of "Why?" Washington DC is a uniquely mal-designed, badly governed, historically burdened city and school district; it will tend to under perform other US cities for that reason.

In case it is not clear, I think equating NAEP scores to grade levels is bogus.

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