Suspension of face-to-face instruction in schools during the COVID-19 pandemic has led to concerns about consequences for students’ learning. So far, data to study this question have been limited. Here we evaluate the effect of school closures on primary school performance using exceptionally rich data from The Netherlands (n ≈ 350,000). We use the fact that national examinations took place before and after lockdown and compare progress during this period to the same period in the 3 previous years. The Netherlands underwent only a relatively short lockdown (8 wk) and features an equitable system of school funding and the world’s highest rate of broadband access. Still, our results reveal a learning loss of about 3 percentile points or 0.08 standard deviations. The effect is equivalent to one-fifth of a school year, the same period that schools remained closed. Losses are up to 60% larger among students from less-educated homes, confirming worries about the uneven toll of the pandemic on children and families. Investigating mechanisms, we find that most of the effect reflects the cumulative impact of knowledge learned rather than transitory influences on the day of testing. Results remain robust when balancing on the estimated propensity of treatment and using maximum-entropy weights or with fixed-effects specifications that compare students within the same school and family. The findings imply that students made little or no progress while learning from home and suggest losses even larger in countries with weaker infrastructure or longer school closures.

COVID-19 大流行期间学校暂停面对面教学，引发了人们对学生学习后果的担忧。到目前为止，研究这个问题的数据还很有限。在这里，我们使用荷兰极其丰富的数据（ n ≈ 350,000）评估学校停课对小学成绩的影响。我们利用全国考试在封锁前后进行的事实，并将这一时期的进展情况与前三年同期进行比较。荷兰只经历了相对较短的封锁期（8周），并拥有公平的学校资助制度和世界上最高的宽带接入率。尽管如此，我们的结果显示学习损失约为 3 个百分点或 0.08 个标准差。其影响相当于一个学年的五分之一，即学校保持关闭的同一时期。来自教育程度较低家庭的学生的损失高达 60%，这证实了人们对这一流行病对儿童和家庭造成的影响不均的担忧。通过调查机制，我们发现大部分效果反映了所学知识的累积影响，而不是测试当天的短暂影响。当平衡估计的治疗倾向并使用最大熵权重或使用比较同一学校和家庭内的学生的固定效应规范时，结果仍然稳健。研究结果表明，学生在家学习时几乎没有进步，甚至没有进步，而在基础设施薄弱或学校停课时间较长的国家，损失甚至更大。