Table 1.

Characteristics of query topics screened for fit with coronavirus disease (COVID-19) case data.

Search query category	Unique queriesa, n (%)	Correlation with national case rateb, mean	Associated lag time (days)c, mean	Activity weightingd
COVID-19 guidance	32 (6.9)	0.96	9.1	0.38
COVID-19 news	57 (12.3)	0.96	8.3	1.00
COVID-19 symptoms	91 (19.7)	0.94	8.9	0.41
Medical treatments	34 (7.3)	0.93	10.1	0.31
COVID-19 testing	58 (12.5)	0.89	5.4	0.11
Medical care	33 (7.1)	0.89	7.2	0.60
Nonspecific symptoms	62 (13.4)	0.89	6.8	0.57
Economic effects	28 (6.0)	0.86	5.9	0.12
Unrelated to illness	51 (11.0)	0.86	6.6	0.76
Symptoms of other illnesses	17 (3.7)	0.84	8.3	0.77

^aNumber of queries of each type in the query library (eg, the category “COVID-19 testing” would include the specific query “coronavirus test near me,” and the category “nonspecific symptoms” would include the query “cough”).

^bExpressed as the inverse z-transformation of the averaged z-transformed correlations with in-sample national data.

^cMean lag time between best-fitting query activity and confirmed case rate, in days.

^dRelative mean search activity levels, normalized.