Tuesday, December 29, 2020

Scale and Symmetry in Covid Debates

One curious feature of some public debate about Covid policy is when people object to a disliked policy proposal by appealing to a consideration that counts at least as much against the alternative.  Here I'll just highlight a couple of especially striking examples of this: scale and unknown risks.

(1) Scale:  Back when people were debating whether society's response might end up being worse than the disease, it wasn't unusual to see health boosters emphasize the sheer scale of the health costs that would be incurred along the path to herd immunity through natural infection.  "Even a fatality rate of just 0.01% for younger adults would translate into thousands of deaths across that population."  That kind of thing.

Which invites the obvious response: Yes, the scale of a pandemic makes the policy stakes really high!  For example, if you lower everyone's quality of life by an average of 1/3 for a year, that translates into more than 100 million life-years of equivalent value lost in the US alone (cf. estimated health gains of a few million life-years from covid prevention measures).

Of course, that's just a made-up illustration.  Maybe average quality of life has not declined so much. But the essential point remains that any non-trivial cost imposed across an entire population results in massive total damages.  And it's not hard to see how the indirect costs of the pandemic could add up here.  There are nearly 50 million parents living with children under 12 in the US.  28 million of those have children under 6.  How many of those families suffered due to childcare and school closures, loss of park and playground access, or stress about their kids' educational and social development?  How many would rate this year as positively detrimental to their global wellbeing? Would many rate this year as even half as good as usual?  (If that was the average verdict, it would yield an aggregate cost of 25 million years among this subpopulation alone.)

Now run through similar questions for college students (how many would happily trade a few months off their life expectancy in return for a normal college experience?).  For the millions who lost their jobs. For those who are simply lonely. And so on.

Of course, it's not all one-sided.  Some of the greatest indirect harms stem from the virus itself rather than social responses to it -- for example, fears for the health of loved ones, and grief at the health costs they end up suffering. (We need to be careful here, though: if an elderly relative would otherwise have died a few years later, there may be no net change to the total grief felt by others from their death as such: it's just moved up in time.  Social restrictions on being with them in their final weeks may make more of a difference. But we can certainly count indirect harms relating to those suffering from "long Covid", at least.)  My point is just that considerations of scale do not straightforwardly favour the health-booster position.  If anything, the social harms seem likely to be greater in terms of sheer scale.

(2) Unknown risks from inoculation: The severity of the virus -- including the risk of long-term side-effects, uncertainty about who might end up having hidden vulnerabilities, etc. -- is often appealed to as a knee-jerk objection to the idea of inoculation via low-dose controlled infection.  But in a context (like the US) where the alternative involves widespread uncontrolled infections, it's unclear why the severity of the illness is a reason to favour the status quo.  The greater the risk posed by the illness, the greater the value of the protection that's provided by a safer, low-dose exposure.

(Of course, it's a fine consideration to appeal to in other contexts, e.g. to argue for targeted inoculation to support suppression efforts while waiting for a vaccine, rather than widespread inoculation in pursuit of early herd immunity.  So I'm only here criticizing indiscriminate forms of this objection.)

Both of the above examples seem to involve a distinctive kind of symmetry error: seeing a potential cost to a policy, but failing to notice that it applies at least as detrimentally to the relevant alternative.  It's worth recasting many objections in an explicitly comparative light.  Instead of rejecting a pandemic policy proposal as "too risky" (as though the status quo in a pandemic were risk-free), ask whether it is more risky than the alternative.  And instead of rejecting a policy for imposing great costs, ask whether it is more costly than the alternative.  The answers may surprise you.


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