Mixed evidence on the relationship between school closure and COVID-19 prevalence could reflect focus on large-scale levels of geography, limited ability to address endogeneity, and demographic variation. Using county-level Centers for Disease Control and Prevention (CDC) COVID-19 data through June 15, 2020, two matching strategies address potential heterogeneity: nearest geographic neighbor and propensity scores. Within nearest neighboring pairs in different states with different school closure timing, each additional day from a county’s first case until state-ordered school closure is related to 1.5 to 2.4 percent higher cumulative COVID-19 deaths per capita (1,227–1,972 deaths for a county with median population and deaths/capita). Results are consistent using propensity score matching, COVID-19 data from two alternative sources, and additional sensitivity analyses. School closure is more strongly related to COVID-19 deaths in counties with a high concentration of Black or poor residents, suggesting schools play an unequal role in transmission and earlier school closure is related to fewer lives lost in disadvantaged counties.

关于学校停课与 COVID-19 流行率之间关系的混合证据可能反映出对大范围地理水平、解决内生性问题的能力有限以及人口变化的关注。使用县级疾病控制和预防中心 (CDC) 截至 2020 年 6 月 15 日的 COVID-19 数据，两种匹配策略可以解决潜在的异质性：最近的地理邻居和倾向得分。在具有不同学校关闭时间的不同州的最近邻对中，从一个县出现第一个病例到州下令学校关闭之间每增加一天，人均 COVID-19 累计死亡人数就会增加 1.5% 至 2.4%（一个县有 1,227-1,972 人死亡）人口中位数和人均死亡人数）。使用倾向评分匹配、来自两个替代来源的 COVID-19 数据得出的结果是一致的，以及额外的敏感性分析。在黑人或贫困居民高度集中的县，学校停课与 COVID-19 死亡的关系更为密切，这表明学校在传播中发挥着不平等的作用，而较早关闭学校与贫困县的死亡人数较少有关。