U.S. Travel Restrictions from China Did Not Significantly Slow Spread of Covid-19
A new paper published as part of the Cato Working Papers (www.cato.org/workingpapers) posits that travel restrictions imposed from China did not halt transmission of the novel Coronavirus into the United States. The authors write that, "Historically, travel restrictions to prevent the spread of pandemic influenzas have been ineffective at halting or significantly delaying the spread (WHO Writing Group, 2006)." They use what is called the synthetic control method (SCM) to estimate a "counterfactual" (meaning, something has not happened or is not the case) number of COVID-19 cases for the U.S. in the absence of the February 2, 2020 travel restriction (Abadie, 2019; Abadie et al., 2010, 2015; Abadie et al., 2003; McClelland et al., 2017). "We use four different outcome variables to measure [the] number of COVID-19 cases: the cumulative number of new COVID-19 cases, the cumulative number of COVID-19 cases per million, the number of new cases, and the number of n...