Archive for representative samples

coronavirus counts do not count

Posted in Books, pictures, Statistics with tags , , , , , , , , on April 8, 2020 by xi'an

Somewhat by chance I came across Nate Silver‘s tribune on FiveThirtyEight about the meaninglessness of COVID-19 case counts. As it reflects on sampling efforts and available resources rather than actual cases, furthermore sampling efforts from at least a fortnight.

“The data, at best, is highly incomplete, and often the tip of the iceberg for much larger problems. And data on tests and the number of reported cases is highly nonrandom. In many parts of the world today, health authorities are still trying to triage the situation with a limited number of tests available. Their goal in testing is often to allocate scarce medical care to the patients who most need it — rather than to create a comprehensive dataset for epidemiologists and statisticians to study.”

This article runs four different scenarios, with the same actual parameters for the epidemics, and highly different and mostly misleading perceptions based on the testing strategies. This is a highly relevant warning but I am surprised Nate Silver does not move to the rather obvious conclusion that some form of official survey or another, for instance based on capture-recapture and representative samples, testing for present and past infections, should be implemented on a very regular basis, even with a limited number of tested persons to get a much more reliable vision of the status of the epidemics. Here, the French official institute of statistics, INSEE, would be most suited to implement such a scheme.