Search for an Illinois community -- or a Chicago neighborhood -- to see the progression of an area's positivity rate, which is the percentage of people tested for coronavirus, who have positive results. NBC5 Investigates uses the daily numbers supplied by the Illinois Department of Health, and the IDPH formula, to compute these daily rates. The state wants an overall positivity rate, for its four regions, to stay under 20 percent. However, the state publicizes a slightly different rate -- the "positive test rate" -- which is the percentage of tests that are positive for coronavirus, out of all tests conducted. This counts repeated tests on the same people, and is nearly always lover than the "case positivity rate" listed here. "