Table 2.

Time-lag correlation coefficients between new COVID-19 cases, Google Trends, and NAVER relative search volumes related to the coronavirus test in South Korea.

Day		Google Trends	NAVER
			Gender		Age groups (years)
			Men	Women	Overall	≤18	19-24	25-29	30-34	35-39	40-44	45-49	50-54	≥55
–3 days
	r	N/Aa	0.739 b	0.769	0.770	0.595c	0.681	0.654	0.701	0.734	0.696	0.624	0.612c	0.441
	P value		<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001
–2 days
	r	N/A	0.769	0.790	0.797	0.505	0.650	0.687	0.752	0.786	0.692	0.673c	0.581	0.445
	P value		<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001
–1 day
	r	N/A	0.795 b,c	0.799	0.824	0.500	0.725 c	0.645	0.775	0.826 c	0.704	0.630	0.532	0.434
	P value		<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001
0 days
	r	N/A	0.778	0.799	0.812	0.542	0.720	0.653	0.746	0.783	0.755 c	0.559	0.551	0.358
	P value		<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001
1 day
	r	N/A	0.775	0.823 c	0.828 c	0.508	0.682	0.688c	0.786 c	0.814	0.718	0.586	0.557	0.450c
	P value		<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001
2 days
	r	N/A	0.756	0.802	0.805	0.549	0.620	0.623	0.774	0.762	0.731	0.586	0.537	0.433
	P value		<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001
3 days
	r	N/A	0.744	0.763	0.781	0.465	0.572	0.606	0.694	0.756	0.633	0.633	0.518	0.424
	P value		<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001	<.001

^aN/A: not applicable.

^bItalics represent strong correlations with r>0.7.

^cStrongest correlation for each column.