so caveat: i could very well be wrong and don't want to seem like i am sure that I am right, but here is my reasoning behind each of these
BiochemAg97 said:
What is the basis of when you switch back to polynomial in the daily death curve?
short answer is my basis is what fits the data the best. I have cells where i can adjust that point back and forth and change the shape of each curve segment and just played with it until it seemed like a good match. the biggest unknown at this point is what do you call the "peak" in the polynomial curve (both date and quantity) as that is the single biggest influence in the final numbers. i chose 4/15 because my first simple "best fit" curve place it there and that matched the date the healthdata.org folks were predicting so i took that date and held it constant. my other basis was that on one of my other plots, i noticed the daily death total was starting to lay very nicely on a polynomial curve so i felt like that supported the case that we had already (if recently) made that transition
Quote:
Do you think exponential decay is the best model for the tail? The deaths should lag the infections by a relatively fixed time. I don't really have a feel for anything better and a long tail on infections and deaths does make sense for something that is going to stick around but we can keep things at a low level.
I think it is the best for a couple of reasons.
1) i don't know of a better option. unless we lock down 100% until all cases resolve, a steep decline isnt going to take us all the way to 0. now it could potentially be harmonic decline, but i haven't had the time yet to build that in.
2) china's tail is exponential decline. now there is a lot of reasonable doubt about their reported numbers, but that's the shape of their curve for whatever that's worth
3) that's the shape of the tail on seasonal flu after each season peaks. so my thinking is that as we open things back up, slowly enough to keep from causing a second peak, it would be reasonable to expect to see a long tail.
a lot of assumptions going on in this tail, and i'll be able to better forecast it once we see a decline (as a PETE decline forecasting is actually something i know a bit about). but for now this is my modeled forecast. hopefully worth slightly more than you paid for it.