Better Together? Heterogeneous Effects of Tracking on Student Achievement
利用德国各州教育制度差异，研究发现延长综合教育对低成就学生数学和阅读成绩有正面影响，而高成就学生不受影响，表明早期分轨可能损害公平与效率。
Abstract I study the effects of early between-school ability tracking on student achievement. My research design exploits institutional differences between German federal states: in all states about 40% of students transition to separate academic-track schools after comprehensive primary school. Depending on the state, the remaining student body is either directly tracked between two additional school types or taught comprehensively for another two years. Comparing these students before and after tracking in a triple-differences framework, I find evidence for positive effects of prolonged comprehensive schooling on mathematics and reading scores. The average effects are almost entirely driven by low achievers, while effects for high achievers are null. Early and rigid forms of tracking can thus impair both the equity and the efficiency of school systems.