The Association of Opening K-12 Schools with the Spread of COVID-19 in the United States: County-Level Panel Data Analysis

TL;DR

This study analyzes county-level data in the US to assess how opening K-12 schools, especially in-person, influences COVID-19 case growth, highlighting the impact of safety measures like mask mandates.

Contribution

It provides empirical evidence linking school openings and visits to increased COVID-19 spread, with causal interpretation and robustness checks.

Findings

In-person K-12 school openings increase case growth by about 5 percentage points.

Counties without mask mandates for staff experience stronger associations.

Results are robust to different timing assumptions and model specifications.

Abstract

This paper empirically examines how the opening of K-12 schools and colleges is associated with the spread of COVID-19 using county-level panel data in the United States. Using data on foot traffic and K-12 school opening plans, we analyze how an increase in visits to schools and opening schools with different teaching methods (in-person, hybrid, and remote) is related to the 2-weeks forward growth rate of confirmed COVID-19 cases. Our debiased panel data regression analysis with a set of county dummies, interactions of state and week dummies, and other controls shows that an increase in visits to both K-12 schools and colleges is associated with a subsequent increase in case growth rates. The estimates indicate that fully opening K-12 schools with in-person learning is associated with a 5 (SE = 2) percentage points increase in the growth rate of cases. We also find that the positive association of K-12 school visits or in-person school openings with case growth is stronger for counties that do not require staff to wear masks at schools. These results have a causal interpretation in a structural model with unobserved county and time confounders. Sensitivity analysis shows that the baseline results are robust to timing assumptions and alternative specifications.