The Costs Of Overreaction V. Underreaction

Steve Sailer has a good post this morning that's worth considering carefully in light of the news coming out of Europe--and what we can glean of the news in the US: Is Boris Johnson's "Controlled Burn" Policy Wise?

The blog itself is long, but what I'll quote comes from Dylan Morris, “PhD candidate in Ecology and Evolutionary Biology interested in mathbio, popgen, and viruses, among other things,” Princeton, NJ.

Morris first summarizes the UK "strategy" (and he's more respectful than to use "" like I just did):

There was a tendentious fight about “herd immunity”, but since then the Govt’s position has been clarified to be as follows. Given: 

a) restrictive control measures carry social and economic cost 

b) behavioral research suggesting people will only comply for a short time… 

The most restrictive and effective control measures should not be imposed immediately. They should be used during a period of rapid epidemic expansion, thus maximizing the number of cases averted. This is more efficient than playing your ace on the first hand.

If you've been following what I've been writing, the problem with this is that when an epidemic is building toward exponential--i.e., for practical purposes, uncontrolled--increase, growth always appears to be slow ... until it's not.


So Morris goes on to explain his reservations about the UK "strategy":

I see two problems with this approach: 

...

1) Asymmetry 

It is far easier to back off from too strong an initial response than to salvage matters after an insufficient one. 

As measures are imposed, the UK can monitor case count growth. If numbers of new cases start to decline, controls can be relaxed. 

But if the UK’s initial response undershoots what is needed, it may become too late for even an ultra-aggressive China style response to stop the British healthcare system from being overwhelmed. 

Why? Exponential growth magnifies modeling errors. If the Govt’s model estimates for (a) current cases (b) control measure effectiveness or (c) time to implementation are off, the epidemic could reach overwhelming size before the Govt has a chance to course correct. 

In short, overreactions are costly, but underreactions are costly too. And everything we know suggests underreactions are just as plausible as overreactions in situations like these, less reversible, and *far, far more costly* 

2) Aggressive measures pay greatest dividends early

Morris proceeds to provide epidemiological theory with lots of statistical modeling concepts, but he concludes:

So there’s in fact no reason to hold your Ace in the hole. Your most powerful control measures should come out early, and then you can gradually relax them as the controlled burn goes on. This is more or less what the democracies of East Asia have achieved. 

This avoids the asymmetry problems of trying to time things for maximum efficiency, but it also provides a clear solution to problems of compliance and frustration with control measures: people get the worst over with immediately, and things just get more relaxed from there. 

In short, I see both frightening risk and false economy in the UK’s strategy as I understand it, and I would urge them to consider why Taiwan and South Korea see things differently.

President Trump appears to be coming to that conclusion and it also appears to be the consensus of the American people: Let's get this thing under control NOW.