Learning that Lasts: Understanding Variation in Teachers' Effects on Students' Long-Term Knowledge
Measures of teachers’ “value added” to students’ current test performance feature prominently in ongoing reforms to teacher evaluation systems. However, this immediate effect may not capture teachers’ more meaningful longer-term impact on student learning. Set in New York City, this study investigates the persistence of teachers’ effects. Two findings emerge. First, a teacher’s effect on students’ English Language Arts achievement has substantial crossover effects on long-term math performance. Second, the persistence of teachers’ value-added is considerably lower in schools that serve more low-achieving students or that hire fewer academically skilled teachers. The results provide evidence that teachers’ effects on students’ long-term skills can vary substantially as a function of both instructional content and quality.