Where the study jumps off the rails is linking all of the relative increase in virus cases in counties with attendees compared to those without rally participants. The modelers multiplied the percent increase in cases for counties with attendees by their pre-rally cumulative cases to get a total of 263,708 additional cases—266,796 including South Dakota’s increase.
But many “high inflow” counties like Los Angeles, Maricopa (Arizona), Clark (Nevada) and El Paso were experiencing flare-ups before the rally. These counties may have shared other characteristics like higher population density that contributed to their increases. There could be other “endogenous” variables—for instance, counties with more people who attended the motorcycle rally may also have had populations less observant of social distancing.
The study’s authors nonetheless assign each of these 266,796 Covid cases a public-health cost of $46,000—ergo $12.2 billion—though the vast majority of all virus cases are mild or moderate. Talk about a case study in statistical overreach—and double standards.