Relative Age, Class Assignment, and Academic Performance: Evidence from Brazilian Primary Schools
利用巴西小学按年龄排名分班的规则，研究发现被分到年龄较大的班级会使临界点学生的数学成绩下降约0.4个标准差，且年龄异质性是重要原因。
Abstract Students in Brazil are typically assigned to classes based on the age ranking in their cohort. I exploit this rule to estimate how fifth‐grade students’ achievement in mathematics is affected when they are in classes with older peers. I find that being assigned to the older class leads to a drop in maths scores of about 0.4 of a standard deviation for students at the cut‐off. I provide evidence that heterogeneity in age is an important factor behind this effect. Information on teaching practices and student behaviour sheds light on how class heterogeneity harms learning.