Big numbers
I've been trying various ways to figure out, when all is said and done, how many people world-wide are likely to die from this COVID scourge. I've been hampered by the fact that statistics was my worst subject in university, even though I'm endlessly fascinated by the behaviour of datasets. That makes me just knowledgeable enough to be dangerous. I accept that my conclusions are endlessly debatable, but right now all such results are debatable, so I don't feel too bad.
Based on the global statistics, it looks to me like the eventual Case Fatality Rate for identified cases and deaths will be around 6%. I derived this from the published global case and death data going back to mid February. I calculated ten sets of ratios, one based on the each day's deaths divided by the same day's cases, all taken from worldometer. Then, based on the idea that one day's deaths may be better correlated with some previous day's cases (because it take a while for identified cases to die), I created 9 more series by dividing each day's deaths by the cases on each of the nine previous days.
I graphed all ten series of CFR percentages, and got a set of nested curves, all of which rose and then turned back down. I put a well-fitting trend line on each curve, extended it out about 2 weeks, and found something very interesting. The curves all crossed at the 6% point, except the one using same-day data. I'm not enough of a statistician to tell you why that intersection might have happened, but my pattern-recognition circuits all lit up when I saw it. The graph is below.
Ass a sort of cross-check, I extrapolated the global curves for identified cases and deaths out 14 days, and used the end-points of those two projections to calculate the projected CFR six weeks from now. Again, the answer was about 6%. (graphs below)
So, absent any more reliable estimate at this point in the pandemic, I've adopted 6% as my tentative CFR. I'll watch the behaviour of the data as time goes on, to see of the estimate changes.
Applying this to the future state of the world, assuming an identified infection rate of 10%, a CFR of 6% implies about 48 million deaths worldwide.
As far as the USA is concerned, a 10% infection rate and a 6% CFR projects 2 million deaths, which is within the range of the high-level projections revealed by Dr. Birx.
Obviously these are little more than wet-finger estimates because it's still early days. They will obviously change as time goes on and the results of social distancing and lockdowns are felt (or not) in different places. But it does hint at the death tolls we should be prepared for.
This so sucks.
= new reply since forum marked as read
