JMIR Publications

ABSTRACT

Background:

Wireless emergency alert (WEA), which delivers disaster information directly to individuals’ mobile phones, has been widely used to provide information related to coronavirus disease (COVID-19) and to encourage compliance with social distancing guidelines in the COVID-19 pandemic.

Objective:

This study aimed to empirically analyze the effect of WEAs on the floating population where WEAs were transmitted in the early stages of COVID-19 pandemic. As most WEA messages focus on compliance with the government’s social distance guidelines, one of the goals of transmitting WEA in the COVID-19 pandemic is to control the floating population at an appropriate level.

Methods:

We investigate the empirical impact of WEA on the floating population across 25 districts by estimating a panel regression model at district-hour level with a series of fixed effects. Main independent variables are the number of instant WEAs, the daily cumulative number of WEAs, the total cumulative number of WEAs, and information extracted from WEAs by a natural language processing at district-hour level. The dataset provides a fine empirical setting as WEAs were sent by different local governments with various district-hour level data, which is identifiable.

Results:

The estimates of the impact of WEAs on the floating population are significantly negative (-0.012, P<.05 to -0.0144, P<.05) across all specifications, implying that the floating population decreases when people receive WEAs. Although the coefficients of DCN (daily cumulative number of WEAs) are also negative (-0.0034, se:0.0035 to -0.0052 se:0.0035) across all models, they are insignificant. The effect of WEAs on the floating population are doubled (-0.0254, P<0.05 to -0.0331, P<0.01) when the first 82 days of observations were used as subsamples to reduce the possibility of people blocking WEAs.

Conclusions:

Our results suggest that issuing WEAs and distributing information related to COVID-19 to a specific district reduced the floating population of that district. Furthermore, among the various types of information in the WEAs, location information was the only significant information, which causes a decrease in the floating population. Our findings provided a plausible mechanism by which WEA could effectively suppress infectious disease by providing the empirical evidence that the transmitting WEAs affected the reduction of the floating population in the COVID-19 pandemic.