In a landmark ruling, a Los Angeles superior court judge on Tuesday struck down key elements of California’s teacher tenure statutes after finding that the near inability to fire ineffective teachers disproportionately hurts poor and minority students. The ruling rests in large part on what Judge Rolf Treu called ”compelling” academic research that “shocks the conscience.” Highly ineffective teachers, the evidence suggests, can cause lasting harm that reaches far into a student’s future. ”Based on a massive study, Dr. [Raj] Chetty testified that a single year in a classroom with a grossly ineffective teacher costs students $1.4 million in lifetime earnings per classroom,” Judge Treu wrote in his 16-page decision (pdf).
That 2012 study, by Harvard’s Raj Chetty and John Friedman and Columbia’s Jonah Rockoff, analyzed data from 2.5 million kids over two decades, matching test scores with the tax data for the same students and their parents. They tried to isolate how much any individual teacher adds or detracts by comparing how the students scored on end-of-year tests to how similar students did with other teachers, controlling for a host of such things as test scores in the prior year, gender, suspensions, English language knowledge, and class size.