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# 03/23/20 BLOG

03/23/20 BLOG # 8
Dear Friends,

Today I want to write about the crisis from a mathematical point of view. As a mathematician and a retired actuary, I take interest in some of the numbers focused on by the media and others. Several thoughts:

• When the media focuses on the increase in the number of positive cases, they’re sort of missing the point (as Governor Andrew Cuomo keeps says). The number of positive cases will increase as we do more testing. That measure has a certain value, but there are other measures which are more valuable.

• We need to focus on the number of infected people that need to be hospitalized (usually somewhere around 14% of those infected) because we are expected to have a shortage of hospital beds.

• We need to focus on the number of infected people that need to be in hospital ICUs (usually somewhere around 5% of those infected) because we are expected to have a shortage of ICU beds and respirators.

• And, of course, we need to focus on the number of deaths since, ultimately, that tells us whether we’re winning the war against coronavirus. Of the people infected, scientists think about 1% to 3% are dying. Attached are snapshots reported on 3/23/20, of the number of deaths, by day, in the world and in the U.S., respectively. Obviously, both bar graphs show that the number of daily deaths is growing exponentially. These are some of the curves to be flattened.
SEE ATTACHMENT – ITEM # 7 AND ITEM # 8

• When it comes to the number of deaths, we need to focus on whether the number of deaths (each month, week or day) reflect a patter that is increasing or decreasing. One way scientists do this is to look at the “doubling factor” – how long does it take for the number of deaths (in a given population, such as the world, or a country, or a state) to actually double. (Deaths doubling in two days is, of course, much worse than deaths doubling in, say, 14 days.) To best understand this, look at the interactive graphs (one by country and one by state) at https://nyti.ms/2UcjlBD. I think the “NY Times” (to which I have a subscription) is updating these graphs regularly and making them available to anyone, even if you don’t have a subscription. As of 3/23/20, those graphs show the following for those countries with at least 25 deaths:
o Doubling every 11 months – China (who is getting things under control compared to the rest of the world – in other ways, they’re “flattening the curve.”)
o Doubling every 14 days – South Korea
o Doubling every 6 days – Iran
o Doubling every 4 days – Italy (although they were once in much worse shape)
o Doubling every 3 days – France
o Doubling every 2 days – Spain, and the United States.
And that same website shows the following for states with at least 10 deaths:
o Doubling every 8 days – Washington
o Doubling every 6 days – Florida
o Doubling every 4 days – California
o Doubling every 3 days – New Jersey
o Doubling every 2 days – New York, Georgia

• Again, when we speak of “flattening the curve,” we are speaking of curves other than how many tests have been performed. Politically, the U.S. is being looked at as behind many other countries in testing, when you look at the number of tests per million population.
SEE ATTACHMENT – ITEM # 9