Our daily update is published. States reported 870k tests, 57k cases, 40k currently hospitalized, and 994 COVID-19 deaths. Note: Updates were not available from FL, GA, and AL. 
On 10/16, IA reclassified ~10k tests from PCR to antigen, causing its totals to drop. NV redesigned its dashboard and removed the number of people who tested negative, a figure we used to calculate totals. We froze the figure, making NV’s tests appear as all positive for 5 days.
We’ve received a lot of questions recently about high daily test positivity calculations for states, ranging from 50%-100%, based on dividing our Positive API field by our totalTestResults API field.
These high daily test positivity figures are symptoms of state reporting problems. Our testing data reflects the number of tests reported by states rather than the number of tests occurring in a state on a given day. (Only some states only make date of testing figures available).
Collecting data by date of report allows our API to reflect the most up to date figures from states. But, if a state’s data pipeline falters for a day, we also pick up on those reporting problems, which would be corrected in the retroactive data.
This can lead to fluctuations in test positivities with our API. If a state only reports positive tests on a given day due to a technical problem with negative reporting, it will appear as if they have a 100% test positivity for that day, like what happened in Nevada this week.
Should you encounter an anomalously high test positivity from any source, we recommend investigating the state’s reporting to see if there were any data issues before assuming the test positivity actually rose dramatically.
The COVID Tracking Project does not currently calculate test positivity rates, and will not do so until we are confident in our ability to document all these fluctuations and variations in test positivity between states.
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