The Effect of Large-Scale Anti-Contagion Policies on the Coronavirus (COVID-19) Pandemic

Solomon Hsiang; Daniel Allen; Sebastien Annan-Phan; Kendon Bell; Ian Bolliger; Trinetta Chong; Hannah Druckenmiller; Andrew Hultgren; Luna Yue Huang; Emma Krasovich; Peiley Lau; Jaecheol Lee; Esther Rolf; Jeanette Tseng; Tiffany Wu

It is also possible that changing public information during the period of our study has some unknown effect on our results. If individuals alter their behavior in response to new information unrelated to anti-contagion policies, such as news reports about COVID-19, this could alter the growth rate of infections and thus affect our estimates. Because the quantity of new information is increasing over time, if this information reduces infection growth rates, it would cause us to overstate the effectiveness of anti-contagion policies. We note, however, that if public information is increasing in response to policy actions, then it should be considered a pathway through which policies alter infection growth, not a form of bias. Investigating these potential effects is beyond the scope of this analysis, but it is an important topic for future investigations.