To what extent does in‐person schooling contribute to the spread of covid‐19? evidence from michigan and washington

In this paper we use data from Michigan and Washington on COVID case rates at the county level linked to information on the instructional modality offered by local public school districts during the 2020/2021 school year to assess the relationship between modality and COVID spread. We focus primarily on COVID case rates, but also provide estimates for hospitalizations (in Washington only) and deaths. District and month fixed effects models that exploit within-district (over time) variation in instructional modality and account for time-invariant district factors show that, in both states, in-person/hybrid schooling relative to remote instruction can lead to increases in COVID spread in communities with moderate to high levels of preexisting COVID cases. Event study estimates show sharp increases in Michigan case rates after a district opens for in-person or hybrid schooling, but these largely fade out over two months.