Is this controlling for the distribution of the population age?
You should probably computed the incidence, give a persons age in each country. Then, you can take any age distribution, re-weight the incidence in each country with that, and you will get an informative metric.
See just above the map: "This has been age-standardized, assuming a constant age structure of the population for comparisons between countries and over time.". This is what you suggests IIUC?
You should probably computed the incidence, give a persons age in each country. Then, you can take any age distribution, re-weight the incidence in each country with that, and you will get an informative metric.