Q: June 12, 2010 Defective Link
Hi, Ed, Thank you for sharing the Epidemic Lab. I notice the link in the Q&A section for May 31 [Economic Benefits of Social Distancing] links to a page with the error message: “This site can’t be reached.”
A: Thank you for the catch.
I notice some links to articles critical of the government response to the epidemic - have a short life.
The response now stands with a replacement link.
Q: May 31, 2010 Epidemic-Lab Questions
Ed, I visit your site with considerable interest and have some questions about the Overview chapter at the Help tab.
1. You have six stages of epidemic. I wonder where you have the Recovered stage.
2. How do you consider the length of time a person remains Susceptible; one could remain Susceptible indefinitely and subject to exposure from several sources.
3. What do you mean by "Normal Organic Rate?" How do you determine that? Can you have lifetime immunity?
A: Thank you for reading the material carefully and for asking direct and perceptive questions.
1. The model has no "Recovered" stage. It has people recovering from Exposed, Infected and Bedridden and flowing to Immune. The rest wind up in Deceased.
In the model, you can adjust the Transfer-Forward fractions for Exposed, Infected and Bedridden. You can also adjust the Durations people remain in these stages.
You also have an option of modeling the loss of immunity by re-cycling a fraction of Immune back to Susceptible.
The model allows you to experiment with your own assumptions to find ones that you consider reasonable and that also generate simulations that fit your experience.
2. You may adjust the Duration of Susceptible by setting Viral Heat. Viral Heat, a property of the virus itself, informs the conversion of Susceptible to Exposed.
3. You obtain the The Normal Organic Rate of conversion when you allow the epidemic to proceed without interventions such as distancing, treatments or vaccines. The organic rate depends on viral heat, a property of the virus itself. Various studies put this rate for COVID-19 initially as exponential growth with doubling period of about 5 days. Later, as fewer Susceptible remain, the rate falls, tracing out a bell-shape pattern.
You can set the Duration of Immunity to anything from temporary to permanent. Temporary immunity implements by recycling Immune back to Susceptible.
Q: Mayo 31, 2020 Reportando desde Bogotá
Ed, Si me equivoco en mi apreciación respecto a tu estudio, me corriges.
Entiendo que en la investigación manejas varias variables y que aplica el distanciamiento, cantidad de gente expuesta ya contagiada y la gráfica señala la probabilidad de contagio, así como la tasa de mortalidad.
Mi humilde concepto es que la cifras que publican los medios no son reales y que si hay gente como tu que si estudie las variables para establecer las que se pueden controlar, vamos a tener correctivos oportunos pero es que ni la OMS ni los gobiernos tiene cifras reales y muchos de los procedimientos para atacar el problema son ensayo y error.
Si no respondo a tu objetivo me excusas, leo y escucho cosas diferente y hasta contradictorias todos los días.
Mi admiración por trabajar en búsqueda de la verdad del asunto.
Sigo confinada en casa y sometida a la evolución de la pandemia para poder visitar a mi familia ...
A: Gracias por compartir sus sentimientos y su proceso.
Yo también encuentro que los medios publican informes confusos y conflictivos.
Mi modelo intenta formalizar las definiciones de etapas y flujos principales. Con suerte, puede dar sentido a la situación, para mí y para los demás.
Q: May 31, 2020 Economic Benefits of Social Distancing
Ed, A recent study by Michael Greenstone and Vishan Nigam indicates substantial economic benefits from social distancing. These experts seem to contradict your model.
A: Thank you for raising this issue. The Greenstone/Nigam study (March 2020) relies on the Ferguson three-stage model (Imperial College). See: link for an expert opinion about the Ferguson model upon which the UK and other governments rely.
The G/N study also incorporates a VSL (value of a statistical life) of around $10,000,000 per person. This follows from their assumption that the average American would willingly pay $10,000 to avoid a 0.1% chance of death.
The G/N study does not present a strong distinction between prevention and postponement.
From their assumptions the G/N study goes on to justify governments spending lots of money to achieve these enormous "savings." Note: these savings disappear with a lower VSL value, say the value to which the average American actually insures his own life: about $100k. I notice the study does not recommend offering people in hospital beds an opportunity to monetize their remaining days in favor of their families at the $10MM rate.
The Epidemic-Lab presents a working six-stage model; it lets you experiment with various policies to see for yourself what works and what does not work.
I conclude that we likely now sit near the end of an enormous disturbance: 10% of it from a novel virus and 90% of if from a Govopoly System growing increasingly wild in its 39-th day.
I invite model builders, epidemiologists and experts of all stripe to visit my Lab and offer comments, criticisms and suggestions on how to improve it.