The Hubei-based forecast is keeping up, but not by much.
I supposed I shouldn't be too hard on myself - it's not every FReeper who forecasts this sort of thing AND publishes their results. Further, it's not in my nature to explain away my own faulty forecast. But today's 76% growth in confirmed cases *MAY* be due to more testing being done here in the US.
The sun will come out tomorrow, and hopefully the rate of confirmed case growth abates. Right now we're looking more like Germany in that regard. I'm a man of my word so I'm going to keep publishing these results until Apr 15; if you'd like to be dropped from this ping please let me know.
| Date | Forecast Cases: Hubei Pattern | Forecast Percent Growth | Actual Cases | % diff: Actual-Forecast Cases | Logistic Forecast: 1/(1+exp(-( -3.2392+0.1988*day of the epidemic)))*41500 | % diff: Actual-Logistic Forecast Cases |
| 3/14/20 | 2,999 | 38.0% | 2717 | -9% | 3,315 | -18% |
| 3/15/20 | 3,552 | 18.4% | 3478 | -2% | 3,974 | -12% |
| 3/16/20 | 4,376 | 23.2% | 4645 | 6% | 4,748 | -2% |
| 3/17/20 | 6,837 | 56.3% | 6362 | -7% | 5,650 | 13% |
| 3/18/20 | 8,271 | 21.0% | 7769 | -6% | 6,693 | 16% |
| 3/19/20 | 10,202 | 23.3% | 13680 | 34% | 7,885 | 73% |
| 3/20/20 | 12,029 | 17.9% | . | . | 9,233 | . |
| 3/21/20 | 13,526 | 12.4% | . | . | 10,739 | . |
| 3/22/20 | 15,264 | 12.8% | . | . | 12,395 | . |
| 3/23/20 | 16,577 | 8.6% | . | . | 14,189 | . |
| 3/24/20 | 18,125 | 9.3% | . | . | 16,099 | . |
| 3/25/20 | 19,408 | 7.1% | . | . | 18,096 | . |
| 3/26/20 | 20,410 | 5.2% | . | . | 20,144 | . |
| 3/27/20 | 20,410 | 0.0% | . | . | 22,204 | . |
| 3/28/20 | 29,488 | 44.5% | . | . | 24,236 | . |
| 3/29/20 | 33,280 | 12.9% | . | . | 26,201 | . |
| 3/30/20 | 34,408 | 3.4% | . | . | 28,066 | . |
| 3/31/20 | 35,590 | 3.4% | . | . | 29,806 | . |
| 4/1/20 | 36,696 | 3.1% | . | . | 31,401 | . |
| 4/2/20 | 37,731 | 2.8% | . | . | 32,842 | . |
| 4/3/20 | 37,945 | 0.6% | . | . | 34,125 | . |
| 4/4/20 | 38,196 | 0.7% | . | . | 35,255 | . |
| 4/5/20 | 38,331 | 0.4% | . | . | 36,238 | . |
| 4/6/20 | 39,201 | 2.3% | . | . | 37,086 | . |
| 4/7/20 | 39,201 | 0.0% | . | . | 37,811 | . |
| 4/8/20 | 39,325 | 0.3% | . | . | 38,427 | . |
| 4/9/20 | 39,630 | 0.8% | . | . | 38,947 | . |
| 4/10/20 | 39,875 | 0.6% | . | . | 39,384 | . |
| 4/11/20 | 40,125 | 0.6% | . | . | 39,749 | . |
| 4/12/20 | 40,320 | 0.5% | . | . | 40,054 | . |
| 4/13/20 | 40,579 | 0.6% | . | . | 40,307 | . |
| 4/14/20 | 40,927 | 0.9% | . | . | 40,517 | . |
| 4/15/20 | 41,047 | 0.3% | . | . | 40,691 | . |
You should declare victory and withdraw the troops!
What if you tweak the parameters of the exponent in your logistic function to make the curve more closely fit the data that’s coming in?
I don’t know exactly how you came up with those numbers, but obviously they entailed some educated guesswork. Adjusting these factors IN NO WAY invalidates your essential hypothesis—that this SARS coronavirus can be effectively modeled by a logistic function of the same form as other SARS.
The key questions remain:
1) What is the number of actual cases reached by the time the curve flattens?
2) When is this flattening achieved?
The bad news is I still suck as a virus forecaster, but anyone who shoots knows that if you're pulling left, all you need to do is make an adjustment. It seems that the US growth rate pattern since March 14 is more correlated with that of Hubei starting on Jan 24 vs Jan 30 (which is my starting point). However, I'm sticking to my bad forecast for now. Besides, you never know...the Red Sox beat the Yankees after trailing by three games to win the Pennant a few years ago.
I've introduced a new column, of % daily growth in confirmed US Cases. I think this helps flesh out where we were, and where we're going...and how bad I'm failing. Rock on.
| Date | Forecast Cases: Hubei Pattern | Forecast Percent Growth | Actual Cases | % Daily Growth in Actual Cases | % diff: Actual-Forecast Cases | Logistic Forecast: 1/(1+exp(-( -3.2392+0.1988*day of the epidemic)))*41500 | % diff: Actual-Logistic Forecast Cases |
| 3/14/20 | 2,999 | 38.0% | 2717 | 25% | -9% | 3,315 | -18% |
| 3/15/20 | 3,552 | 18.4% | 3478 | 28% | -2% | 3,974 | -12% |
| 3/16/20 | 4,376 | 23.2% | 4645 | 34% | 6% | 4,748 | -2% |
| 3/17/20 | 6,837 | 56.3% | 6362 | 37% | -7% | 5,650 | 13% |
| 3/18/20 | 8,271 | 21.0% | 7769 | 22% | -6% | 6,693 | 16% |
| 3/19/20 | 10,202 | 23.3% | 13680 | 76% | 34% | 7,885 | 73% |
| 3/20/20 | 12,029 | 17.9% | 19285 | 41% | 60% | 9,233 | 109% |
| 3/21/20 | 13,526 | 12.4% | . | . | . | 10,739 | . |
| 3/22/20 | 15,264 | 12.8% | . | . | . | 12,395 | . |
| 3/23/20 | 16,577 | 8.6% | . | . | . | 14,189 | . |
| 3/24/20 | 18,125 | 9.3% | . | . | . | 16,099 | . |
| 3/25/20 | 19,408 | 7.1% | . | . | . | 18,096 | . |
| 3/26/20 | 20,410 | 5.2% | . | . | . | 20,144 | . |
| 3/27/20 | 20,410 | 0.0% | . | . | . | 22,204 | . |
| 3/28/20 | 29,488 | 44.5% | . | . | . | 24,236 | . |
| 3/29/20 | 33,280 | 12.9% | . | . | . | 26,201 | . |
| 3/30/20 | 34,408 | 3.4% | . | . | . | 28,066 | . |
| 3/31/20 | 35,590 | 3.4% | . | . | . | 29,806 | . |
| 4/1/20 | 36,696 | 3.1% | . | . | . | 31,401 | . |
| 4/2/20 | 37,731 | 2.8% | . | . | . | 32,842 | . |
| 4/3/20 | 37,945 | 0.6% | . | . | . | 34,125 | . |
| 4/4/20 | 38,196 | 0.7% | . | . | . | 35,255 | . |
| 4/5/20 | 38,331 | 0.4% | . | . | . | 36,238 | . |
| 4/6/20 | 39,201 | 2.3% | . | . | . | 37,086 | . |
| 4/7/20 | 39,201 | 0.0% | . | . | . | 37,811 | . |
| 4/8/20 | 39,325 | 0.3% | . | . | . | 38,427 | . |
| 4/9/20 | 39,630 | 0.8% | . | . | . | 38,947 | . |
| 4/10/20 | 39,875 | 0.6% | . | . | . | 39,384 | . |
| 4/11/20 | 40,125 | 0.6% | . | . | . | 39,749 | . |
| 4/12/20 | 40,320 | 0.5% | . | . | . | 40,054 | . |
| 4/13/20 | 40,579 | 0.6% | . | . | . | 40,307 | . |
| 4/14/20 | 40,927 | 0.9% | . | . | . | 40,517 | . |
| 4/15/20 | 41,047 | 0.3% | . | . | . | 40,691 | . |