A number that tells us we need more testing | Opinion - Kitsap Sun

Ronald D. Fricker Jr., professor of statistics at Virginia Tech and former faculty member in the Operations Research Department of the Naval Postgraduate School explains, The U.S. has performed more coronavirus tests than any other country in the world. 

Photo: Matilda Wormwood from Pexels

Yet, at the same time, the U.S. is notably underperforming in terms of suppressing COVID-19. Confirmed cases – as well as deaths – are surging in many parts of the country. Some people have argued that the increase in cases is solely due to increased testing.

I am a statistician who studies how mathematics and statistics can be used to track diseases. The claim that the increase in cases is only caused by increases in testing is just not true. But how do public health officials know this?

Testing, confirmed cases and total cases
COVID-19 testing has two purposes. The first is to confirm a diagnosis so that medical treatment can be appropriately rendered. The second is to do surveillance for tracking and disease suppression – including finding those who may be asymptomatic or only have mild symptoms – so that individuals and public health officials can take actions to slow the spread of the virus...

A good way to think about test positivity is to think about fishing with a net. If you catch a fish almost every time you send the net down – high test positivity - that tells you there are probably a lot of fish around that you haven’t caught – there are a lot of undetected cases. On the other hand, if you use a huge net – more testing – and only catch a fish every once in a while – low test positivity – you can be pretty sure that you’ve caught most of the fish in the area.
Read more...

Source: Kitsap Sun