COVID-19 numbers are reported by number cases, which is good to know, but hard to compare when you have populations that are vastly different. You can’t just compare the US numbers to the Chinese numbers given the Chinese population is roughly 4.25X the US population. That’s partly why it’s crazy that the US COVID-19 numbers are already surpassing the Chinese numbers, and just within a few week of when things started getting serious! You’d be looking at like 350,000 cases in China if the same thing were happening, not 80,000!!!
Being able to compare by prevalence, or how widespread something is “per capita” of a population, is why I made this Tableau viz for a better comparison. I started with just the Canadian provinces, though, due to less complicated data. I will be back with one for global data by the end of this upcoming weekend, I hope, and will link it here.
Looking at the Canadian data, I see that my little province of Nova Scotia, with about 0.95 million people, is doing worse than the big province of Ontario that is shutting down more than we are. That said, they should be, because the potential for maximum damage that can be done for them is like 10X that for us, especially with potential hot spots of huge populations like the city of Toronto.
Prevalence won’t tell you that story, no. But neither will case totals. However, what prevalence will still tell you is your general odds of a sudden exponential growth. Nova Scotia, as small in comparison to Ontario as it might be, has enough concentrated population centers that our current higher odds of an outbreak compared to Ontario will make us more susceptible to one than they are, and one with devastating enough damage to be feared, even if not an utterly catastrophic one like Toronto might see. In that sense, having prevalence awareness is highly useful, and frames things in a useful context that should be part of the whole picture, but one that I haven’t really seen reported anywhere… which is why I went to make the graphic myself.