I apparently forgot to hit Publish Post on this when I wrote it Monday afternoon...
If for some reason you haven't read Dana Milbank's column in Kaplan Test Prep Daily, On education policy, Obama is like Bush, you should. Milbank is a douche, but this piece is impressively on-point.
And I can't improve on Corey Bunje Bower's analysis of The Great LA Time Value Added Kerfuffle of Ought-Ten:
*Teacher quality varies widely within schools -- just as with test scores, there's far more variation within schools than across schools ("Teachers are slightly more effective in high- than in low-API schools, but the gap is small, and the variance across schools is large"). Which means that the highest performing schools don't have all the best teachers and the lowest performing schools don't have all the worst teachers. Which means that something other than teacher quality is causing schools to be low and high performing. Which means we should probably focus our attention on more than just teacher quality.
*There's an extremely weak correlation between how the schools fare in the state API rating system and how they fare in a measure of "school effects" that controls for all sorts of factors. As Buddin writes, "About a fourth of low-API schools have above average school value added relative to other elementary schools in the district. Similarly, about a fourth of the highest-quartile API schools have below average school effectiveness. The overall message is that many schools with low achievement levels are producing strong achievement gains and many schools with high achievement levels are producing weak achievement gains for their students."
*I'm not sure exactly how large the teacher effects are, but looking at the info they provide, with the exception of a few outliers, they don't appear to be earth-shatterlingly huge. The methodology paper says that a student with a teacher one standard deviation above normal would move from the 50th to 58th percentile in ELA. If I'm doing my math right (which I might not be -- it's late), that means that 2/3 of teachers, on average, move their students up or down less than one-fifth of a standard deviation each year. The article mentions a teacher who's ranked among the top 5% of all elementary school teachers whose students gain, on average, 4 and 5 percentile points in ELA and math in a given year.
*The article mentions a teacher held in high-esteem at one of the highest scoring schools who performs far below average according to the value-added scores. According to the article, her principal thinks she's a great teacher as do the kids and parents in her school. This means that either a.) principals, kids, and parents aren't good judges of teacher quality (at least sometimes), and/or b.) what people define as a good teacher only somewhat overlaps with what teachers can do to boost value-added scores
Who will be surprised if sometime around 2018 the Gates Foundation announces that, surprise, while teachers vary in quality, teacher quality is not actually responsible for or the solution to the achievement gap.