Covid-19 cases rose together in Minnesota and its neighbors, and they are falling together too
On December 11th, Health Commissioner Jan Malcolm said:
“The good news is that over the last couple weeks, we have seen a leveling off…I think that’s because our governor put a 4-week pause into effect…”
The data doesn’t support this argument. Minnesota’s Covid-19 case numbers started improving before Gov. Walz’s latest shutdown went into effect on November 20th: as Figure 1 shows, new cases peaked at an average of 6,823 for the seven days up to and including November 11th and the ratio of tests returning positive results peaked at 18.4% on November 10th.
Figure 1: New cases of Covid-19 and ratio of tests positive in Minnesota, seven-day moving average
Source: Department of Health
But there is another reason to be skeptical of Commissioner Malcolm’s claim. That is the data from Minnesota’s neighbors.
Figure 2 shows data from The COVID Tracking Project for Minnesota and its neighbors for the number of new cases per million of the population averaged over seven days. We see the same pattern in each state. There is a marked upward surge in the rate of new cases between mid-August and mid-September rising to peaks in mid-November, before falling away quite rapidly up to the present.
Figure 2: New cases of Covid-19 per million of the population, seven day moving average
Source: The COVID Tracking Project
This is in spite of the various policies pursued by these states. On mask mandates, for example, Minnesota has had one in place since July 25th, Wisconsin since August 1st, North Dakota since November 14th, Iowa since November 17th, and South Dakota not at all. Both Iowa and North Dakota could point to the fact that their imposition of mask mandates came at the peak of new cases and was followed by a sharp decline and deduce that they were successful. But the evidence of the other three states ought to give them pause. Minnesota and Wisconsin have long had mandates in place, South Dakota hasn’t, and all got hit with a surge at more or less the same time that subsided at the same time.
So it is with shutdowns. The New York Times notes that businesses are ‘Mostly open’ in all of Minnesota’s neighbors with our state the only one of the five where they are ‘Mostly closed’. Even so, when it comes to cases, we have seen a pattern little different to that in Wisconsin, Iowa, South Dakota, or North Dakota.
Is all this just incredible coincidence? Was Gov. Walz’ latest round of shutdowns such a potent weapon that it pushed down Covid-19 numbers in neighboring states? Or is there some other factor at work, such as geography and/or seasonality? If it is the latter, this suggests that measures such as shutdowns and mask mandates have only small effects. And it is against these smaller beneficial effects that we must weight their cost.
John Phelan is an economist at the Center of the American Experiment.