I tried to answer the same question here and got very different numbers—somewhere between 500 and 2000 cases now.
I can’t see your images or your spreadsheet, so I can’t tell exactly where we diverged. One possible issue is that AFAIK most people start showing symptoms after 5 days. 14 days is the preferred quarantine period because it’s almost the maximum amount of time the disease can incubate asymptomatically; the average is much lower.
That seems like a very likely divergence point. The difference between an incubation period of 5 days and of 14 days is an extra 1.3 to 2.5 doubling times. I might do up the same calculations with variable incubation period tomorrow.
The google sheet is shared now. It really is kind of messy though, more like scratch paper than a published document.
Actually, I was previously assuming that people are diagnosed the day they develop symptoms, which is probably an unrealistic expectation. If I add a term for that, and assume that there’s a 5 day lag, my numbers jump up again:
I tried to answer the same question here and got very different numbers—somewhere between 500 and 2000 cases now.
I can’t see your images or your spreadsheet, so I can’t tell exactly where we diverged. One possible issue is that AFAIK most people start showing symptoms after 5 days. 14 days is the preferred quarantine period because it’s almost the maximum amount of time the disease can incubate asymptomatically; the average is much lower.
That seems like a very likely divergence point. The difference between an incubation period of 5 days and of 14 days is an extra 1.3 to 2.5 doubling times. I might do up the same calculations with variable incubation period tomorrow.
The google sheet is shared now. It really is kind of messy though, more like scratch paper than a published document.
Alright, when I change the incubation time to 5 days, and correct a formula error, I get the following:
Upper bound (assuming a 3.5 day doubling time and a 5% confirmation rate): 6,837 infected persons.
Lower bound (assuming a 7 day doubling time and a 70% confirmation rate): 384 infected persons.
...which are a lot closer to your estimates.
Actually, I was previously assuming that people are diagnosed the day they develop symptoms, which is probably an unrealistic expectation. If I add a term for that, and assume that there’s a 5 day lag, my numbers jump up again:
Upper bound: 17,100
Lower bound: 585
I just fixed the images for Eli.
Thanks Oli.