As COVID-19 ravaged the US in the first quarter of 2020, the US lacked a uniform mandatory policy for containing its spread. Governors facing enormous opposing pressures from businesses and medical professionals adopted various policies, especially lockdowns. The authors statistically analyze...

Lockdowns and stay-at-home orders in response to the Covid-19 pandemic have raised an urgent question in peoples’ minds, “How long must these restrictions last?” We propose two metrics of the spread of disease to answer this question: daily growth rate and time to double cumulative cases....

Lacking a federal policy to control COVID-19, state governors ordered lockdowns and mask mandates, at different times, generating a massive natural experiment. The authors exploit this natural experiment to address four issues: 1) Were lockdowns effective in reducing infections? 2) At what costs...