Fig. 3.

The schematic of COVID-19 case and UMD-CTIS surveillance signal benchmarking globally. For each country and territory, the 7-d smoothed COVID-19 case counts from Our World in Data (A) are compared to the survey-weighted CTIS surveillance measure. (B) The CCLI signal for Bolivia and Italy is shown for illustrative purposes. The survey-weighted sum of “yes” responses to the surveillance questions (here the CCLI survey question) for each week was divided by the sum of survey weights for all surveys over a 7-d window. (C) Time series were normalized to a range of 0 to 1using minimum and maximum during the survey period to allow within- and between-locale comparison of trends across a range of values using color intensity. (D) For each country/territory (rows), we combined normalized time series with log₁₀ of the number of surveys (black bar chart), percent surveys per population (white bar chart), age and gender distributions (stacked bar charts), peak day (solid black circle, benchmark; open colored shapes, signals) and the benchmark–signal correlation strength (green) in the form of an annotated heatmap.