These rankings are important because it helps us get a feel for what type of quarantine action is getting the virus under control.
Any country with sufficient testing that's managed to bring the growth rate below exponential is worth an enormous amount of attention, because we seem to have many countries who have taken action yet failed to stop exponential growth.
Then use cases/capita. US has 330 million people and comparing it with #2 spot (Italy with 60 million) is completely insane, not to mention that the worse is yet to come to US.
I am all for taking a critical look at American systems and their effectiveness of the response, but the ranking by the case numbers is naive, misleading and unproductive.
Every country starts with (let's say) 1 imported case. From there, it grows. Cases/capita doesn't really mean anything until you get into the millions of cases and start thinking about what the upper bound might be.
And so ranking countries by size of outbreak seems reasonable to me.
I edited my comment with some data. The onset is staggered, the entire ranking thing is useless until the pandemic is over. It is simply a tracker, not an objective measure of the efficacy or the effectiveness of the measures each country is taking. It is too soon.
> we seem to have many countries who have taken action yet failed to stop exponential growth
Remember the virus has an incubation period of around 2 weeks. China's numbers appeared to be increasing exponentially for 2 weeks after the lockdown, but those were mostly people infected before the lockdown.
Any country with sufficient testing that's managed to bring the growth rate below exponential is worth an enormous amount of attention, because we seem to have many countries who have taken action yet failed to stop exponential growth.