On July 23, 2020, we switched our **Total tests** units to the people-tested metric reported by the Northern Mariana Islands, which led to a drop in total tests. We will backfill total tests data for the territory as soon as we are able to do so.Negative test results reported in our API and CSVs are calculated by subtracting **Positive PCR tests (people)** from **Total PCR tests (people)**.