Why is it useful to look at biweekly changes in confirmed cases?

For all global data sources on the pandemic, daily data does not necessarily refer to the number of new confirmed cases on that day – but to the cases reported on that day.

Since reporting can vary significantly from day to day – irrespectively of any actual variation of cases – it is helpful to look at a longer time span that is less affected by the daily variation in reporting. This provides a clearer picture of where the pandemic is accelerating, staying the same, or reducing.

The first map here provides figures on the number of confirmed cases in the last two weeks. To enable comparisons across countries it is expressed per million people of the population.

And the second map shows the growth rate over this period: blue are all those countries in which the case count in the last two weeks was lower than in the two weeks before. In red countries the case count has increased.