The effectiveness and costs of nonpharmaceutical interventions for COVID-19 containment: A border discontinuous difference-in-difference approach

We examine the effectiveness and costs of alternative nonpharmaceutical interventions (NPIs) for COVID-19 containment. Using a border discontinuous difference-in-difference approach, we find that the enforcement of rigid NPIs reduces the number of new COVID-19 cases by 10.8% in China, comparied with cities with less NPIs. Among the three NPIs, contact tracing is much more effective than the other two NPIs, namely, public information provision and social distancing. The connections of mayors to the upper-level politicians reinforce the city's implementation of rigid NPIs. These networks also serve as an informal signaling channel to the neighboring cities, encouraging the adjacent cities to impose strict NPIs to curb the spread of COVID-19. We further estimate the long-term costs of the NPIs – a net present value of 2153 yuan per child in the human capital loss attributed to more prolonged school closure alone.