The WHO tells us to “Test, Test, Test” and Testing forms a key part of South Korea’s strategy of “Trace, Test & Treat”.
Because only by testing can we expect to really know how active the virus is in our communities.
And only if we know that can we use additional measures to stop the spread of the virus.
Above, this graph shows RoI is doing the most tests in countries shown & have detected 2nd most cases per million population.
Above, this another way of showing the same testing data:
On the left for each country we see total number of tests divided by positive cases
On the right for each country we see number of deaths divided by number of positive cases, multiplied by 100
A high propensity to testing (e.g. South Korea, where they do nearly 50 tests to find 1 positive case) leads to a better picture of where virus is active.