Stay at Home to Stay Safe: Effectiveness of Stay-at-Home Orders in Containing the COVID-19 Pandemic

Abstract

Despite the outbreak of the COVID-19 pandemic, there has been an ongoing debate regarding the effectiveness of the stay-at-home order implemented in many states. While proponents believe that the order helps reduce person-to-person contacts and therefore the spread of the pandemic, opponents argue that the order is unnecessary and hurts the economy. In this study, we use eight states that did not implement the order as a control group and six neighbor states that implemented the order as a treatment group to estimate the effect of the stay-at-home order. We find that, though residents in both groups have already voluntarily stayed at home, the order reduces the number of new COVID-19 cases by 7.6%. To understand the mechanisms behind these results, we compare the mobility of residents in the control and treatment groups over time. We find that the stay-at-home order significantly increases residence mobility (i.e., movement at home) and reduces the mobility at transit station, work place, retail and recreation. The results of this study are useful to policy makers as they conduct cost-benefit analyses of back-to-work plans vs. stay-at-home policies and decide whether to implement, extend, or lift a stay-at-home order amid a pandemic such as COVID-19. Our results are also useful to researchers as we highlight the importance of correcting for potential selection issues. As we illustrate in this study, ignoring potential selection issues would lead to the wrong conclusion that the stay-at-home order increases the number of new cases.