According to the text of the Vergara decision, two expert witnesses for the plaintiffs were Professor Raj Chetty of Harvard and Professor Tom Kane of Harvard.
Professor Chetty, the judge said, testified that “a single year in a classroom with a grossly ineffective teacher costs students $1.4 million in lifetime earnings per classroom.” Dr. Kane testified that students in LAUSD taught by a teacher in the bottom 5% of competence lose 9.54 months of learning in a single year compared to students taught by an average teacher.
Chetty, you may recall, is the nation’s leading proponent of VAM. Kane directs the Gates Foundation’s MET (Measures of Effective Teaching) Project.
The judge accepted these statements as fact, not knowing they are strongly disputed by other scholars.