Hoffman: Percentage Of Positive COVID-19 Tests Is Increasing Slowly In New Mexico And Colorado

The fraction (as a percentage) of daily tests that come back positive, for New Mexico and Colorado. The dots show the daily percentage, and the solid lines show the percentage over a 5-day period centered on the date plotted. Created by Nels Hoffman
By NELS HOFFMAN
Los Alamos
Recent news accounts describe an increasing daily number of new covid-19 cases around the US. But to judge how serious the situation is, it’s important to look not just at the number of new cases, but also at the number of new tests that are done every day.
That way, we avoid lulling ourselves into a false sense of security, if there happen to have been rather few tests that day, and therefore a small number of positive tests. We also avoid a false sense of panic, if there happen to have been a large number of tests that day, and therefore a large number of positive tests. 
So, to take into account the rate of testing as well as the number of newly reported cases, the figure above shows the fraction (as a percentage) of daily tests that come back positive, for New Mexico and Colorado. The dots show the daily percentage, and the solid lines show the percentage over a 5-day period centered on the date plotted.
In Colorado, the 5-day rate of positives dropped as low as 3.5 percent in mid-June, but is now back up to nearly 5 percent. In New Mexico, the 5-day rate of positives was down to 2.5 percent in mid-June, but is now over 3 percent. So yes, the rate of positives is increasing in these two states, but fairly slowly so far, rather than showing a “spike”. Still, the Colorado increase from 3.5 percent to 5 percent represents more than a 40 percent increase in the positive rate – something to be concerned about.
Created by Nels Hoffman
There will probably always be covid-19, into the indefinite future. The question is whether testing will become so common and frequent that we’ll be able to find outbreaks quickly, and whether we will have a vaccine soon.