This appeal, to be decided by the United States Court of Appeals for the 11th Circuit, challenges two egregious misuses of "value-added modeling," a controversial teacher evaluation method that attempts to isolate the affect of one teacher on the learning gains of that teacher's students, as derived from annual standardized test scores. With the approval of the State Appellees, the School District Appellees used the test scores of students who took the Florida Comprehensive Assessment Test in reading and math to evaluate the teaching performance of teachers who either did not teach these students at all, or did not teach them the tested curriculum. Amici, who are experts in education, education law, and educational measurement, file this brief to assist the Court in understanding how irrational these uses of value-added modeling are. The uses challenged here contradict the very purpose of using value-added modeling in the first place. In addition, they completely lack scholarly support, and they undermine, rather than further, the state's avowed purpose in evaluating its teachers -- to incentivize the evaluated teachers to improve their teaching, and thereby improve student achievement.