The Models Redux

Nature has an interesting piece on the models and their advocates. Before commenting one should recall the old adage: Generals make many war plans, but after the first gun has fired, they are all thrown out and actions are taken on the fly. One need look no further than the classic War Plan Orange, war with Japan, which totally missed Pearl Harbor.

So if we at times see this process as ad hoc, just look at some of our prior wars. Nothing is necessarily what it appears to be.

This gets us to models. I have a few, and I have done well over a thousand for various businesses and investments. I can assure one that reality never matched the model, never. Models do help you to think about issues but ultimately there is always the "Oh s..t" moment. That is when the war usually begins.

The Nature piece states:

Governments across the world are relying on mathematical projections to help guide decisions in this pandemic. Computer simulations account for only a fraction of the data analyses that modelling teams have performed in the crisis, Ferguson notes, but they are an increasingly important part of policymaking. But, as he and other modellers warn, much information about how SARS-CoV-2 spreads is still unknown and must be estimated or assumed — and that limits the precision of forecasts. An earlier version of the Imperial model, for instance, estimated that SARS-CoV-2 would be about as severe as influenza in necessitating the hospitalization of those infected. That turned out to be incorrect. The true performance of simulations in this pandemic might become clear only months or years from now. But to understand the value of COVID-19 models, it’s crucial to know how they are made and the assumptions on which they are built. “We’re building simplified representations of reality. Models are not crystal balls,” Ferguson says.

Frankly and in my opinion based upon my experience the Ferguson model is not only incomplete, ineffective but as I have noted previously reckless.

The key to any model here is understanding the transmission mechanism. It is fair to say we really do not yet have a grasp on it. Face masks not withstanding, is it a virion transmission of some form from an infected individual to an uninfected one. This virus grows at 37C which means not the nose but the lungs. There  ideas that it may get to one's face and then actually move by some heat sensing mechanism. That is one of a thousand tales.

It is critical to understand this mechanism and any model without a clear well accepted mechanism is a waste of time and yes indeed reckless.