Tag Archives: testing

For Anyone

…who believes that, “we have more cases because we have more testing”.

Testing for an infectious disease is like counting the number of balloons in a dark room by tossing darts through the doorway. Say you throw 10 darts in the room and hear two pops. There is still a good chance that a number of balloons remain uncounted. But if you throw 40 darts in the room and hear two pops, the likelihood of a two-balloon scenario soars. When the rate of pops drops below a certain proportion, you can be sure that you have counted most of the balloons in the room. A low percentage of positive tests is what you’re after.
Once you have established the adequacy of your testing, you can sort out what the results reveal about containment. The raw numbers don’t tell you that much. In the case of national case counts, it is reasonable to expect a country with a large population to experience higher numbers than a country with a small population given similar degrees of disease containment. A true measure of containment is cases per population, or in our analogy, how crowded the room is with balloons.
So when a pinhead like Trump says that we have more cases because we have more testing, that standalone statement is pure bull shit. What’s worse, it’s a distraction from what really indicates the adequacy of our understanding of the outbreak’s extent and the effectiveness of our efforts to contain it: percent positive tests and infections per population.

How is the US doing?

Top of the heap with >15,000 cases/1 million persons (European Centers for Disease Control)

Percent positive tests: 7.9 (an adequate percentage is less than 5%)

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