Of Base Rates and BS

I was having dinner with some good friends last week. He a physician, recently retired; she a principal, head of her own, private middle school. Both are trained thinkers and observers; both experienced in those endeavours. M, the educator, was sneezing and sniffling, apologetically reassuring that her ‘symptoms’ were an allergic reaction — ‘not to the company’, again reassuringly. Never at a loss for conversational topics, she borrowed my napkin (having exhausted her own and husband’s) to ‘mop up’ — and the chat turned to COVID-19. Screen Shot 2020-03-08 at 5.41.43 PM

A significant plank in my friendship with P, the physician, is his grounded, no-nonsense, and (underscore) reality-based view of the world — something I like to think we both share. On long bike rides, he’s fond of sharing his aphorisms and agitations, both the aggregation of long years of practice and exposure to the human condition. He opened the conversation with a query: ‘so what do you think the mortality rate of this one is?’ Reference to the red-plumed snowball pictured above. In short order, followed comparisons between the world’s current obsession and the more mundane, ‘common garden variety’ flu. To wit, the base rates hove into view — that would be the naturally occurring frequency of a phenomenon in a population. And, as it turns out, the former (aka, the bloody snow ball) is running a shade over 2%; the latter, hovering just above 1% — depending on the population sampled, and the particular strain of good, old fashioned, happens every year FLU. Hmm?

So. . . what’s up? Not a simple question. A Harvard epidemiologist estimates that between forty per cent and seventy per cent of the world’s roughly five billion adults will eventually (read, over the next four to five years) contract COVID-19. Having picked oneself off the floor, it may be politic to take a Valium. I recall long term care homes restricting access, hospital wards instituting amped up isolation and containment practices — every year of my four decade’s work in public health facilities. I do not recall quarantined cruise ships, store shelves devoid of toilet paper and rubbing alcohol, cancelation of major public events world wide, stock market catastrophics, condemned countries, boycotting of my favourite Mexican beer, failing economies, and every Tim Horton’s table talk subject (since 9-11) centring on the viral treat of the week.

It’s hard to argue the scenery chewing, centre stage status of an event that will potentially impact up to 3 of 4 folks standing on the planet. Sort of like acne, constipation, teenaged angst, and poor driving habits. But then it’s hard to get behind this latter group as ‘stop the presses, hold the front page’ issues. More like slow news day content — no less widespread, no less distressing, but equally commonplace (read ‘widespresd’). Kind of like flu.

I recall my (much revered) statistics prof’s favoured annual lecture opener: ‘All heroin addicts drink milk!’ Followed by his well-honed treatise on the evils of confusing causal relationships (drinking bossy’s white nectar may not be the point of entry to a lifetime of hard drug abuse) with events that merely coexist with each other. It’s all in the spin. And the angst value. And it’s what (in old-speak) sells papers. To quote Bob (the prof), ‘let’s have a good look at the data — and not the presumption’. He could just as easily have said: ‘keep calm and carry on’ (i.e., don’t panic!!).

Easily overwhelmed by the media’s feeding frenzy, and it’s search for a good, global disaster, a few voices of rationality might be detected — if we listen very (very) hard. Cognitive scientist, Samuel Veissiere is quoted recently:

Covid-19 is turning out to be a remarkably intelligent evolutionary adversary. . . Ebola was a rather stupid virus, because it kills its host. The coronavirus is different: by exploiting vulnerabilities in human psychology it has already shut down many of our schools, crashed our stock market, increased social conflict and xenophobia, reshuffled our migration patterns, and is working to contain us in homogenous spaces where it can keep spreading. The bad news is that people living in densely populated areas are very likely to contract the virus. . . The good news is that most people won’t die of it.

A friend recently reposted the similarly reasoned position of a physician and infectious diseases specialist that certainly merits a re-repost:

I am not scared of Covid-19. What I am scared about is the loss of reason and wave of fear that has induced the masses of society into a spellbinding spiral of panic, stockpiling obscene quantities of anything that could fill a bomb shelter adequately in a post-apocalyptic world. I implore you all. Temper fear with reason, panic with patience and uncertainty with education.

Screen Shot 2020-03-09 at 10.25.40 PMSo I suspect the reasoned position is somewhere between Chicken Little and Marcus Aurelius. Somewhere midway between the sky is falling and the stoic acceptance of the (real) father of cognitive rationality. A good helping of common sense would go a long way. As my (infinitely reasonable) educator friend advises: wash your hands to two full renditions of ‘Happy Birthday’. Certainly beats my usual pass ’em under the hot water tap and wipe ’em on your sleeve!

2 thoughts on “Of Base Rates and BS”

  1. Thank you for this one, David! Such balanced perspectives, based on what can be extrapolated by science and medicine to date, are important to think understand. Paul and I were talking last night about the really feasome “epidemic of stupid” that is plaguing our world…..We keep looking for the spaces of sanity into which we can go to take a break and a fresh breath. It is heartening that we know where to find you…!!

    1. Ah, Carol. Thanks as always for your lovely and thoughtful feedback. I suspect I’m up to two, maybe three ‘followers’ at this point. Very pleased to count you among them!

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