Update: Comparing COVID-19 in Minnesota and its neighbors in Upper Midwest

Updated: May 12, 5 p.m.

As of May 12, Minnesota had 12,494 confirmed cases of COVID-19, the disease caused by the novel coronavirus.

How does that compare to other states in the Upper Midwest? Because of how COVID-19 is being tracked, it isn’t an easy question to answer.

In terms of raw numbers, Iowa has more cases than its larger neighbors, Minnesota and Wisconsin, as of the second week of May. The Dakotas have fewer cases than more populous states in the region.

But 1,000 confirmed cases would mean something very different in a large state like Minnesota or Wisconsin than it would in a small state like North or South Dakota. Here is a look at COVID-19 cases per million residents.

Some smaller states actually have higher rates of COVID-19, adjusting for population, than do larger states with more total cases.

All of these figures exist in an unusual circumstance, however. Tests for COVID-19 remain in short supply in the United States, and many people who wanted to be tested have been unable to do so.

These figures don’t reflect the number of people who may have COVID-19; they only reflect the current number of people who have tested positive. A state that tests fewer people for coronavirus will get fewer positive results, but that doesn’t mean it has fewer people with the disease.

A final factor to consider is how many positive tests states are seeing compared to the number of tests they issue. If a state is rationing its limited supply of tests only to people with the highest probability of COVID-19 infection, they’ll get a higher share of positive results than a state that also tests lower-probability patients.

While Upper Midwest states originally showed a big divide in what share of COVID-19 tests were coming back positive, with more time they converged around a positive rate around 5 percent. But states with major outbreaks have seen that positive rate rise above 10 percent.

So few tests are available in the United States that all of these figures are likely underestimating the number of COVID-19 cases, in part because mild cases of COVID-19 can share many symptoms with more familiar diseases such as the seasonal flu.

Some experts have suggested that death rates are a more reliable way to measure an often-fatal disease such as COVID-19, since they’re more likely to be noted than someone who gets sick with flu-like symptoms. As of early May, Minnesota has the most COVID-19 deaths in the region.

Raw death counts are skewed by population just like cases and tests. Adjusting for population, Minnesota still has more deaths than its neighbors.

MPR News will continue to provide updated information as fresh data becomes available.

Editor’s note (March 19, 2020): This story has been updated to reflect that Iowa stopped reporting total COVID-19 tests. Graphics have also been updated to remove “pending” COVID-19 tests from state’s totals.