Audrey Amrein Beardsley of Arizona State Is one of our nation’s leading experts on matters related to value-added measurement. In this rarified but important field, Beardsley has a stellar advantage: she was a classroom teacher. Imagine that!

She has been following the Vergara trial in Los Angeles closely.

She writes here about the testimony of Harvard professor Tom Kane, who advises the Gates Foundation:

“If I was to make a list of VAMboozlers, Kane would be near the top of the list, especially as he is increasingly using his Harvard affiliation to advance his own (profitable) credibility in this area. To read an insightful post about just this, read VAMboozled! reader Laura Chapman’s comment at the bottom of a recent post here, in which she wrote, “Harvard is only one of a dozen high profile institutions that has become the source of propaganda about K-12 education and teacher performance as measured by scores on standardized tests.”

“Anyhow, and as per a recent article in the Los Angeles Times, Kane testified that “Black and Latino students are more likely to get ineffective teachers in Los Angeles schools than white and Asian students,” and that “the worst teachers–in the bottom 5%–taught 3.2% of white students and 5.4% of Latino students. If ineffective teachers were evenly distributed, you’d expect that 5% of each group of students would have these low-rated instructors.” He concluded that “The teaching-quality imbalance especially hurts the neediest students because ‘rather than assign them more effective teachers to help close the gap with white students they’re assigned less effective teachers, which results in the gap being slightly wider in the following year.”

“Kane’s research was, of course, used to support the claim that bad teachers are causing the disparities that he cited, regardless of the fact the inverse could be also, equally, or even more true–that the value-added measures used to measure teacher effectiveness in these schools are biased by the very nature of the students in these schools that are contributing their low test scores to such estimates. As increasingly being demonstrated in the literature, these models are biased by the types of students in the classrooms and schools that contribute to the measures themselves.”