The Science on Lockdowns

In the past six months, we’ve heard again and again that we have to “follow the science,” often as a voice directing us to hand over more of our liberty to politicians and to accept the massive blow to the economy that they’ve prescribed.  Over time, one gets the sense that the rule only applies in one direction.

When the CDC, for example, provides cover for something a particular politician wants to do, it’s, “We have to follow CDC guidelines.”  When the CDC suggests something different, it’s, “Oh, those are only guidelines, and we’re doing something different.”

So what does “the science” say about lockdowns?  Here’s Donald Luskin, writing in the Wall Street Journal:

TrendMacro, my analytics firm, tallied the cumulative number of reported cases of Covid-19 in each state and the District of Columbia as a percentage of population, based on data from state and local health departments aggregated by the Covid Tracking Project. We then compared that with the timing and intensity of the lockdown in each jurisdiction. That is measured not by the mandates put in place by government officials, but rather by observing what people in each jurisdiction actually did, along with their baseline behavior before the lockdowns. This is captured in highly detailed anonymized cellphone tracking data provided by Google and others and tabulated by the University of Maryland’s Transportation Institute into a “Social Distancing Index.”

Surprisingly, lockdowns are associated with more cases and opening up after having locked down is associated with fewer.  Of course, to some extent, there is a cause-and-effect problem.  The worse the problem is becoming, the more likely leaders will press a lockdown, and the more things improve, the more they’ll open up.  Still…

The lesson is not that lockdowns made the spread of Covid-19 worse—although the raw evidence might suggest that—but that lockdowns probably didn’t help, and opening up didn’t hurt. This defies common sense. In theory, the spread of an infectious disease ought to be controllable by quarantine. Evidently not in practice, though we are aware of no researcher who understands why not.

The key point to take away from this is the scientific one Luskin implies:  We don’t know how to quantify the various contributing factors, but we can say that the numbers provide no proof that dramatic government action helped.

Sure, it makes sense that lockdowns should do something, but “following the science” means requiring evidence.  It would be reasonable (and scientific) to propose hypotheses as to why the numbers don’t reflect our expectations, and we may be absolutely correct.  Indeed, we may come to the correct policy conclusions exactly because we relied on reasoning or principles that weren’t obviously in line with “the science.”

But we shouldn’t use science as a talisman to ward off criticism, especially when it isn’t clear what the science says.

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