Testing: For what purpose?

The hue and cry for millions upon millions of COVID-19 tests to be conducted every day has me a bit baffled. From a management perspective, what public health decisions are going to be made based upon data gathered?

I completely understand why a person would want to be tested to see if they are infected now or were infected and are now carrying antibodies. Makes complete sense to me.

But exactly how will data from these tests impact public policy?  They can certainly record a snapshot in time but how is that relevant to determining public health policy for the near future?

It’s a managerial pitfall to collect data which cannot be used to correct or control the object it measures.

For example, let’s say you know that red sweaters lead to cancer. You decide to measure how many people have red sweaters in cars. Where do you measure this? Do you stop all cars on Monday and count them? How much value does that information have when there may be thousands of people who don’t drive thru your red sweater counting line?  Maybe people wear red sweaters and  stay home or maybe they  drive a route that has no red sweater counting people.

But for the sake of argument, let’s say you count 2,000 people on Monday who have red sweaters out of 20,000 people counted. That is ten percent. Let’s say you decide to count the following Monday and find only 1,000 people out of 20,000 have red sweaters on. What are you going to do with that information? And if that is only 500 people out of 20,000 the following week, what decisions or conclusions are you going to make about red sweaters and cancer that has any value?

Each week the number of red sweaters on people in cars is going to vary in accordance with conditions that you didn’t expect. Like holidays. Like warm weather or cold weather. Like tourists.

Testing and counting may tell you there is more or less of something but it doesn’t tell you why and it doesn’t tell  you if it makes a difference.