Chetty et al. v. Rothstein on VAM-Based Bias, Again
Recall the Chetty, Friedman, and Rockoff studies at focus of many posts on this blog in the past (see for example here, here, and here)? These studies were cited in President Obama’s 2012 State of the Union address. Since, they have been cited by every VAM proponent as the key set of studies to which others should defer, especially when advancing, or defending in court, the large- and small-scale educational policies bent on VAM-based accountability for educational reform.
In a newly released working, not-yet-peer-reviewed, National Bureau of Economic Research (NBER) paper, Chetty, Friedman, and Rockoff attempt to assess how “Using Lagged Outcomes to Evaluate Bias in Value-Added Models [VAMs]” might better address the amount of bias in VAM-based estimates due to the non-random assignment of students to teachers (a.k.a. sorting). Accordingly, Chetty et al. argue that the famous “Rothstein” falsification test (a.k.a. the Jesse Rothstein — Associate Professor of Economics at University of California – Berkeley — falsification test) that is oft-referenced/used to test for the presence of bias in VAM-based estimates might not be the most effective approach. This is the second time this set of researchers have argued with Rothstein about the merits of his falsification test (see prior posts about these debateshere and here).
In short, at question is the extent to which teacher-level VAM-based estimates might be influenced by the groups of students a teacher is assigned to teach. If biased, the value-added estimates are said to be biased or markedly different from the actual parameter of Chetty et al. v. Rothstein on VAM-Based Bias, Again | VAMboozled!:
