Why Nate Silver’s FiveThirtyEight blog is wrong about teacher evaluation
FiveThirtyEight is a blog created by Nate Silver, a famous statistician who developed a system for forecasting player performance in Major League Baseball and accurately predicted the winner of 49 out of 50 states in the 2008 presidential election. A few years ago, he was asked during an online Q & A session at Reddit whether he believes student standardized test scores should be used to evaluate teachers. His response went like:
There are certainly cases where applying objective measures badly is worse than not applying them at all, and education may well be one of those. In my job out of college as a consultant, one of my projects involved visiting public school classrooms in Ohio and talking to teachers, and their view was very much that teaching-to-the-test was constraining them in some unhelpful ways. But this is another topic that requires a book- or thesis-length treatment to really evaluate properly. Maybe I’ll write a book on it someday.
He hasn’t written the book yet, or published anything at length on the topic since. But now, Andrew Flowers, FiveThirtyEight’s quantitative editor, has published a piece on the blog about teacher evaluation with this headline, “The Science of Grading Teachers Gets High Marks.”
In the July 20 post — and in a response to questions I sent him — Flowers defends controversial “value-added modeling” (VAM) research conducted by three researchers that, among other things, predicts long-term student outcomes by using student standardized test scores to evaluate their teachers. One of those outcomes is future earnings, with the researchers predicting how much more students with “effective” teachers can earn vs. students with “ineffective” teachers — with effectiveness measured by VAM.
President Obama cited the research in his 2012 State of the Union address by saying, “We know a good teacher can increase the lifetime income of a classroom by over $250,000.” And a judge in the controversial Vergara v. California case referred to it as evidence to assert that “a single year in a classroom with a grossly ineffective teacher costs students $1.4 million in Why Nate Silver’s FiveThirtyEight blog is wrong about teacher evaluation - The Washington Post: