Re: [Phys-L] Confessions of a Repentant Modeler in a Time of Plague.

[bernard cleyet <bernardcleyet@redshift.com>]

> On 2020/Apr/19, at 16:03, John Denker via Phys-l <phys-l@mail.phys-l.org> wrote:
>
>   A good starting place
> is to assume that R₀ is piecewise constant, punctuated
> by changes in public policy. 


I’ve thought of relating the changes in improvement in policy w/ changes in the doubling time, or more easily seen as the slope of the cumulative cases in a log plot.  I suppose it should be ~ five days after the effective implementation.  Using this I’ll look at some of my plots; for deaths more likely fifteen days?  


In searching for Re. Rho effective I found these:   https://web.stanford.edu/~jhj1/teachingdocs/Jones-on-R0.pdf and  https://en.wikipedia.org/wiki/Basic_reproduction_number. 



 As an example of how sensitive the simplest model from cases, I’ll put in http://cleyet.org/covid-19/USA/California/Monterey%20county/.        The last week of published data were corrected upwards from a mean 2.4 daily cases to 6.1.  This moved the peak forward two weeks.  


bc.  of necessity, simple minded.  


p.s.   The sigmoid formula I use is the intermediate in the number of coefficients offered by KaleidaGraph.