The Impact of School Tracking and Peer Quality on Student Achievement: Regression Discontinuity Evidence from Thailand​

A common educational practice around the world is to track students into classrooms based on ability. However, despite the popularity of tracking, relatively few papers directly identify the impact of being tracked into classrooms with higher or lower peer ability. This paper estimates the impact of being tracked into a classroom with higher ability peers by using data from public middle schools in Thailand, where students are tracked into classrooms based on a preliminary exam taken before 7th grade. Importantly, all teachers, curriculum, and textbooks are identical throughout classrooms. To distinguish the impact of peers from confounding factors due to selection, I apply a regression discontinuity design (RDD) that compares the academic outcomes of students just above and below the threshold. Results indicate that significant increases in peer quality do not improve student GPA. This suggests that any gains due to tracking, at least in Asian contexts similar to this, are likely due to factors other than peer quality, such as curriculum or teacher quality.