On March 11, 2020, the World Health Organization officially declared COVID-19 a global pandemic, causing one of the largest disruptions to schooling in history. The COVID-19 pandemic introduced unprecedented challenges for education research and large-scale assessments of student populations. Both schools and researchers were forced to modify…

Does student-teacher match quality exist? Prior work has documented large disparities in teachers' impacts across student types but has not distinguished between sorting and causal effects as the drivers of these disparities. I propose a disparate value-added model and derive a novel measure of teacher quality--revealed comparative advantage--that…