It does not take a Ph.D. in statistics to see that the total number of cases since the outbreak of the disease is not a measure of where the virus known as SARS-CoV-2 is currently spreading. It is an indirect measure of where it has been up to a given time. To know where the virus is spreading, we should look at new cases of the disease (incidence rates).
Even as a measure of cumulative cases, shading entire countries is misleading. If we want to see where cases have clustered since the recordkeeping started,we could look at the heights of bars placed on top of small, similarly sized geographic regions, where the heights are proportional to the number of cases in each region. Alaska would not stand out in such a graph. Indeed, the Times newsletter has a link to far better infographics from Johns Hopkins University, one of which clearly shows this fact.
Media reporting on only the total number of cases by country promotes false impressions of the incidence and prevalence of the disease across countries. For example, the table below gives approximate numbers for the US and Spain, which have the greatest cumulative numbers of cases as reported today on the Johns Hopkins website. It also includes China, which is ranked 9th in reported cases, and Switzerland (15th).
| Country | Cumulative cases | Population | Relative frequency (cases per 100,000) |
| United States | 788,000 | 328,000,000 | 240 |
| Spain | 204,000 | 47,000,000 | 430 |
| China | 84,000 | 1,400,000,000 | 6 |
| Switzerland | 28,000 | 8,600,000 | 330 |
Spain has only about a quarter of the number of cases reported in the US, but it has almost twice the prevalence of the disease. On the basis of reported cases and population size, China's population has emerged relatively unscathed, and on this scale, the US is by no means the most ravaged -- so far.
No comments:
Post a Comment