Idaho v. Washington - deeper dive on virus data

The Dec. 13 front-page article about the impact of the pandemic on the economies of Idaho and Washington includes a timeline that pairs COVID-19 statistics for each state with a history of restrictions imposed by the governors.

The numbers suggest at first glance that Idaho has done a better job of managing the disease. But there is a problem with these statistics: they are not presented in relation to the states’ populations and one of the statistics, labeled “death rate,” isn’t relevant to the measures taken by the governors.

The death rates provided are, the article notes, “based on cases, not population” — which means this is the statistic usually referred to as the “case fatality rate.” It is calculated by dividing the number of deaths by the number of cases to get the percentage of those who contracted the disease that have died. It is useful for assessing the severity of a disease or the effectiveness of therapies, but it is not the right tool for measuring the results of the governors’ actions.

Governors Little and Inslee have focused on measures designed to achieve the same goal: prevent people from contracting the disease in the first place. To assess prevention you would do better to cite the cumulative cases per 100,000 population and the cumulative deaths per 100,000 population.

I calculated these two statistics for the three dates in the Press article. For these back-of-the-envelope computations, I used rounded-off 2019 population numbers: WA, 7.615 million; ID, 1.787 million.

May 1 Washington: 192.2 cases per 100,000 and 10.8 deaths per 100,000

Idaho: 113.9 cases per 100,000 and 3.6 deaths per 100,000

Sept. 1 Washington: 988.7 cases per 100,000 and 25.2 deaths per 100,000

Idaho: 1,795.6 cases per 100,000 and 22.4 deaths per 100,000

Dec. 10 Washington: 2,568 cases per 100,000 and 37.2 deaths per 100,000

Idaho: 6,604.8 cases per 100,000 and 64.2 deaths per 100,000

Do I present this as an indictment of Governor Little’s policies? No, not my purpose. I want to demonstrate that the data doesn’t justify the complacency about Idaho’s performance that might be fostered by the statistics as presented in the article. And I know that while statistics can inform our judgments, they do not tell the whole story.

Washington state, as the Press article observes, has “a more protocol-compliant population.” We have to consider the Idaho context: Access to testing. State demographics. Population density patterns within the state. The state’s unique political, social, and religious cultures. Stances taken by leaders of the Governor’s own party at the state and local level. Decentralized public health agencies. All of these — and more — are influencing the Governor’s decisions.

I reached out to the reporter to ask about the presentation of the COVID-19 data but haven’t heard back yet. I don’t really believe this is an intentional attempt to skew the data to make Idaho look better. The statistics are accurate, I think, but they just aren’t relevant or presented in a form appropriate for comparing two states so different in size.

And hasn’t that been a national problem for nine months now? Tons of data, but confusion about what is most relevant and how to put it all in perspective. Who knew that a pandemic could challenge our math literacy on top of all the other problems it has presented.

Faye Sweney is a Coeur d'Alene resident.