Expected Value

Now and then, Barack Obama suggests that "Climate Change is the most important challenge of our time." When he does this, he and the alarmists who make up one of his major political constituencies invoke the Precautionary Principle. Wikipedia defines this principle in the following manner:

... if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is not harmful, the burden of proof that it is not harmful falls on those taking an action.

The principle is used by policy makers to justify discretionary decisions in situations where there is the possibility of harm from taking a particular course or making a certain decision when extensive scientific knowledge on the matter is lacking.

It's fascinating that the Obama administration is anxious to apply the Precautionary Principle to a threat that by their own admission is 100 years out. But it's even more fascinating that they resist applying a variant of the Precautionary Principle when faced with a potential Ebola epidemic. They argue that the probability of the Ebola threat in the US is very small; therefore, there no need to take "extreme" measure that might otherwise be dictated by the precautionary principle.

In an in-depth discussion of the difference between the probability of an Ebola outbreak in the US and the expected value associated an with an outbreak, Richard Fernandez makes the following comment:

Parenthetically, what is really interesting is where the “Precautionary Principle” has gone to. The administration used to be really worried about the long shot odds that Michael Mann’s climate model might be right. But it [the administration] doesn’t worry about Ebola odds. Maybe we should apply the Precautionary Principle all of the time or none of the time. But it’s altogether too confusing to apply it in this uneven manner.

In his piece, Fernandez explains that the probability of an Ebola outbreak is quite small. This is the argument made by the CDC and the administration. But the expected value of an outbreak grows dramatically as the number of West African cases of Ebola grows. Unfortunately, it's the expected value that matters.Without getting overly mathematical, Fernandez provides a layman's discussion:

When the CDC says the probability of a diseased person reaching the US is “very small” they are talking about the betting odds, which in our hypothetical example was 12/10,000 or .0012. But remember that expected value has a second term: the stake at the table. If there is one Ebola patient with a .0012 chance of reaching America that is one thing, but if there 10,000 people each with a .0012 chance of getting through that is another. The CDC is saying that they have a revolver with thousands of chambers and only one of them has a cartridge in it. Mobley [a doctor] is saying that’s true but if you keep playing Russian Roulette long enough you’ll eventually hit upon a loaded chamber.

Spin the wheel enough times and eventually Ebola gets lucky. The more Ebola patients there are worldwide the more times you spin the wheel. Dr. Mobley is saying that if the disease keeps exploding in West Africa the wheel will get spun too often. Someone will get through, because even though the chance of arriving is individually small, there are just too many individuals who might potentially try to get through.

As the expected value grows (and it is growing) the only rational approach is to cut off pathways for each potentially infected person from arriving at our borders. That does not mean "isolation"—a strawman that the Obama administration has created. Rather it does mean that every person with a passport from a West African country and every person with an entry/exist stamp from West Africa should undergo the restricted entry protocol I proposed in yesterday's post:

The passport checks ... are a relatively easy first step, followed by in-depth questioning of anyone who has visited West African countries, an in situ medical exam if warranted, and in the extreme, a quarantine period for anyone from West Africa who desires entry into the United States. This would last only as long as the Ebola epidemic rages in West Africa.

Over the past five weeks, WHO and the CDC (and related agencies) have upped their prediction of the total number of Ebola cases in West Africa from 20,000 to 200,000 and now to 1.5 million by January, 2015. The expected value of an outbreak in the US increases with every new estimate.

It is unconscionable that this president and his health agencies have not acted to reduce the expected value of an Ebola outbreak in the US by cutting off the pathways of entry for those who might be potentially infected with the disease.  It's unclear whether politics or political correctness or both are guiding the administration's approach, but one this is certain—they are not being guided by either statistics, or common sense, or reality.