Covid-19 Positive Tests vs. Total Tests

The meaning of each positive test has changed significantly over the course of the pandemic as the extent of testing has changed. The US reached 1.2 million total tests about the time the pandemic peaked in New York state. By the middle of November, we were testing that many people each day. That’s more than 2.5% of the US population every week.

The relationship between positive tests and total tests hints at the effectiveness of testing. In these graphs, positive tests are scaled 10x total tests. So if the heights look equal, that means 10x as many total tests are being performed as are being found positive. Ideally, the positive test area (blue) will be half the height of the total test area (gray), or lower. That represents a positive test rate of 5% or lower.