Indiana’s been understating its coronavirus positivity rate.

The percentage of tests coming back positive peaked at 16.8% in April, and dropped as low as 3.5% in June — it’s 12.1% now, now. But state health commissioner Kris Box says all those numbers are two or three points too low. She says the department discovered a coding error several weeks ago in the software used for Indiana’s COVID dashboard. Box says the department has been working since then to confirm the mistake, and work with independent data scientists on a fix.

Box says the figures will be corrected next Wednesday, when Indiana updates its color-coded risk scores for each of the state’s 92 counties. At the same time, the state will implement a change in the method it uses to calculate county-level positivity, one of the components of the risk score. Until now, the state has taken seven days of daily positivity rates, and averaged those percentages. That method means a one-day spike or lull can throw off the data for the whole week. The state will switch  to a straight average, dividing the number of cases in a week by the number of tests.

Box predicts the effect of that change will be a mixed bag, with some county rates going up and others going down.

The risk scores are used to determine how strict capacity limits should be for mass gatherings. Currently, 24 counties are rated at high risk. Ten others were just downgraded to “approaching high risk,” but won’t have their restrictions loosened until they maintain that improvement for a full week. Gatherings in those 34 counties are capped at 50 people.

Box says while the percentages have been off, the state’s trend line will be the same as it was before, but at a higher level. She says the state’s other virus data, including the numbers of cases, tests, hospitalizations and deaths have been accurate.