"Have We Identified Effective Teachers? Validating Measures of Effective Teaching Using Random Assignment" tested whether a measure created by study authors could identify teachers who are effective at increasing student achievement. The authors used 2009-10 school year data to create a single composite measure of teacher effectiveness; this composite measure included estimates of teacher value-added to student test scores, data from classroom observations of teachers, and responses to student surveys. Then, for the following school year (2010-11), the authors randomly assigned classrooms of students to teachers (to ensure that there were no measured or unmeasured differences in students assigned to each teacher) and then followed the students' academic progress throughout the school year. The authors compared the students' actual academic achievement with their predicted achievement to determine how well the teacher effectiveness measure identified teachers who were improving student performance beyond their expected gains. The study found that the measure of teacher effectiveness created using 2009-10 data was correlated with student achievement measured at the end of 2010-11. On average, students of teachers who were identified as being relatively more effective had higher achievement gains than students of other teachers in the same school, grade, and subject. Although this study aims to identify effective teachers in terms of improved student achievement, it is not eligible for review by the What Works Clearinghouse (WWC) because the study does not include identifiable intervention and comparison groups. This study does not test a specific policy, intervention, or practice. Instead, it assesses whether student achievement can be predicted from a continuous measure of teacher effectiveness.