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....