• Raj Chetty
  • John N. Friedman


Measuring the Impact of Teachers I: Evaluating Bias in Teacher Value-Added Estimates. Raj Chetty, John N. Friedman, 2014, Paper. "Are teachers' impacts on students' test scores ("value-added") a good measure of their quality? One reason this question has sparked debate is disagreement about whether value-added (VA) measures provide unbiased estimates of teachers' causal impacts on student achievement. We test for bias in VA using previously unobserved parent characteristics and a quasi-experimental design based on changes in teaching staff. Using school district and tax records for..." Link