Table 4.

Parameter estimates of the main empirical model: panel regression model using wireless emergency alerts (WEAs) and the floating population at the district-hour level with a series of fixed effects.

	(1) Base	(2) With TCNa	(3) With TCCb	(4) With day
N c	−0.014 (0.0053; P=.01)	−0.013 (0.0050; P=.02)	−0.013 (0.0048; P=.01)	−0.013 (0.0050; P=.02)
DCN d	−0.0052	−0.0034	−0.0039	−0.0037
	(0.0035; P=.15)	(0.0035; P=.34)	(0.0034; P=.26)	(0.0035; P=.30)
Log (TCN)	N/Ae	−0.0019 (0.0005; P=.002)	N/A	N/A
Log (TCC)	N/A	N/A	−0.0012 (0.0006; P=.06)	N/A
Log (Day)	N/A	N/A	N/A	−0.0033 (0.0010; P=.004)
Region FEf	Yes	Yes	Yes	Yes
Weekday FE	Yes	Yes	Yes	Yes
Hour FE	Yes	Yes	Yes	Yes
Region × weekday × hour FE	Yes	Yes	Yes	Yes
Observations	236,775	236,775	236,775	236,775
R 2	0.804	0.804	0.804	0.804
Adjusted R2	0.804	0.804	0.804	0.804

^aTCN denotes the total cumulative number of WEAs in a specific district since January 1, 2020, the beginning of the observation period.

^bTCC denotes the total number of confirmed cases of COVID-19.

^cN: number of WEAs.

^dDCN denotes the daily cumulative number of WEAs in a specific district.

^eNot applicable.

^fFE: fixed effect.