Search or sort by area, rate, or status. An area must have a positivity rate under 20%, for 14 straight days, in order to move to the next reopening phase, according to the Restore Illinois plan. The City of Chicago requires a positivity rate of 15% or below. NBC5 Investigates uses the state of Illinois' formula for computing an area's positivity rate, which is a 7-day average, with a 3-day lag. "Case positivity" is the percentage of people who have coronavirus, out of all tests conducted. 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 lower than the "case positivity rate." Although any rate under 20% is acceptable to the state (other than Chicago), and therefore classified as "ok," we classify rates under 10% as "low" because they also adhere to the stricter standards of the World Health Organization.