We study how multigrading, which is mixing students of different grades into a single class, affects children’s cognitive achievement in primary school. We build instruments to identify the causal effect of multigrading by exploiting an Italian law that controls class size and grade composition. Results suggest that attendance in multigrade versus single-grade classes increases students’ performance on standardized tests by 19 percent of a standard deviation for second graders, and it has zero effect for fifth graders. The positive impact of multigrading for second graders appears to be driven by children sharing their class with peers from higher grades. This last finding rationalizes the absence of a multigrade effect for fifth graders.

中文翻译：

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多级和儿童成就

我们研究了将不同年级的学生混合到一个班级的多分级如何影响儿童在小学的认知成就。我们通过利用控制班级规模和年级构成的意大利法律来构建工具来识别多重评分的因果效应。结果表明，多年级班级与单年级班级的出勤率将学生在标准化考试中的表现提高了二年级学生标准差的 19%，而对五年级学生的影响为零。多年级对二年级学生的积极影响似乎是由孩子们与更高年级的同龄人分享他们的班级所推动的。最后一个发现使五年级学生没有多年级效应合理化。