Human Mobility Restrictions and the Spread of the Novel Coronavirus (2019-nCoV) in China

[chengjun]

随机游走播客 Ep27 方汉明：Structural Or Reduced-Form? We Need Them Both

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(with Long Wang and Yang Yang), Journal of Public Economics, Vol. 191, 2020, 104272.

https://doi.org/10.1016/j.jpubeco.2020.104272

Journal of Public Economics
Volume 191, November 2020, 104272

Highlights

• We quantify the causal impact of human mobility restrictions, particularly the Wuhan lockdown, on the spread of COVID-19.
• We employ DID estimations to disentangle the lockdown effect from panic effect, virus effect, and Spring Festival effect.
• Wuhan lockdown reduced inflows to, outflows from, and within movements in, Wuhan by 76.98%, 56.31% and 55.91%, respectively.
• Without Wuhan lockdown, COVID-19 cases would be 105.27% higher in the 347 Chinese cities outside Hubei province.

Abstract

We quantify the causal impact of human mobility restrictions, particularly the lockdown of Wuhan on January 23, 2020, on the containment and delay of the spread of the Novel Coronavirus (2019-nCoV).

• We employ difference-in-differences (DID) estimations to disentangle the lockdown effect on human mobility reductions from other confounding effects including panic effect, virus effect, and the Spring Festival effect.
• The lockdown of Wuhan reduced inflows to Wuhan by 76.98%, outflows from Wuhan by 56.31%, and within-Wuhan movements by 55.91%. We also estimate the dynamic effects of up to 22 lagged population inflows from Wuhan and other Hubei cities – the epicenter of the 2019-nCoV outbreak – on the destination cities' new infection cases.
• We also provide evidence that the enhanced social distancing policies in the 98 Chinese cities outside Hubei province were effective in reducing the impact of the population inflows from the epicenter cities in Hubei province on the spread of 2019-nCoV in the destination cities.
• We find that in the counterfactual world in which Wuhan were not locked down on January 23, 2020, the COVID-19 cases would be 105.27% higher in the 347 Chinese cities outside Hubei province.

Our findings are relevant in the global efforts in pandemic containment.