Inside the black of box of ability peer effects: Evidence from variation in high and low achievers in the classroom. The Economic Journal Doi

In this paper, we estimate the extent of ability peer effects in the classroom and explore the underlying mechanisms through which these peer effects operate. We identify as high ability students those who are enrolled at least one year ahead of their birth cohort (“skippers”) and as low ability students those who are enrolled at least one year behind their birth cohort (“repeaters”). We show that while there are marked differences between the academic performance and behavior of skippers/repeaters and the regular students, the status of skippers and repeaters is mostly determined by first grade; therefore, it is unlikely to have been affected by their classroom peers (and to suffer from the reflection problem). Using within school variation in the proportion of these low and high ability students across cohorts of middle and high school students in Israel, we find that the proportion of high achieving peers in class has no effect on the academic performance of regular students. In contrast, the proportion of low achieving peers has a negative effect on the performance of regular students. An exploration of the underlying mechanisms of these peer effects shows that, relative t