About a month ago, the government conducted a press-conference reporting the results of various “studies”, each claiming that the lockdown had saved thousands of lives. A few days later, some independent scientists also decided to chime in with their own predictions that broadly supported this idea. Even though a few weeks have passed, I think these claims remain relevant, as another round of lockdowns is contemplated in various parts of the country.
So I decided to examine these claims in a little more detail and found that they were very misleading. In fact if the compartmental models used in these studies teach us anything, it is that lockdowns of the kind witnessed in India — which are imposed early in the epidemic but fail to quash it — may delay fatalities but do not avert them. So, within these models, the efficacy of a lockdown cannot be gauged by simply comparing figures for fatalities at the end of the lockdown with the projected figure for fatalities at the same date without the lockdown.
These models do not account for several important real-world effects: the lockdown has caused a humanitarian crisis, it has restricted access to essential healthcare for other conditions and, to a limited extent, it has also been used to ramp up testing and tracing. Moreover, the lockdown has engendered economic insecurity, and in the longer-run, this makes it harder for people to maintain physical-distancing norms. All these effects are more important than the transient direct effect of the lockdown on fatalities. But given the paucity of currently available data, none of them can be quantified. So epidemiological models are simply not in a position to accurately quantify the impact of the lockdown on fatalities.
If this is the case, what motivates these “studies”? Perhaps the independent groups inadvertently fell into a trap set by the government. But, as for the government-backed studies themselves, the answer seems to be clear. There is widespread concern that the lockdown has failed. So, rather than address these concerns, it is “useful to point to “advanced scientific studies” that “show” that the lockdown has saved thousands of lives. Since people tend to get intimidated by differential equations, this helps to shut down critics.”
I discussed some of this in an explainer for the Scroll today:
I also discuss what these “studies” do in practice, how they get these numbers, why it doesn’t make sense, and some broader concerns about models.
This is a summary of a more technical note (written for internal discussions in the Indian Scientists Response to COVID-19 group) that is available publicly here: https://zenodo.org/record/3901516
Both the technical note and the explainer make very simple points. I only felt compelled to write them in light of the claims above, which have received wide publicity.