I agree with your point, but it's got me thinking about how the early mask guidance was so wrong.
Early in the pandemic, virtually all the major health orgs spread the message "masks for the public don't work". Of course, the real issue was that there was a valid fear that there would be a run on masks and not enough for healthcare workers. There was never any significant evidence masks for the public don't work, on the contrary there was at least some flu-based evidenced that they were beneficial, but at best you could say "we don't know".
So I'm very sympathetic to the authorities trying to give simple messages, but in the end the original guidance really bit them in the ass and made a lot of people lose trust. I wonder if the simpler message could have been "don't use a mask, because it means nobody will be left to treat you when your nurse/doctor needs a mask".
> There was never any significant evidence masks for the public don't work, on the contrary there was at least some flu-based evidenced that they were beneficial, but at best you could say "we don't know"
We aren't supposed to make decisions on medical interventions based on "evidence that X doesn't work". Otherwise, we'd default to just doing stuff until we had evidence that it was worse than doing nothing at all. Literally every failed drug ever tested had a biologically plausible reason for starting the test, and yet we know that most drugs don't work when you take them out of the lab!
Saying that there were some papers out there recommending masks is beside the point, because you can find papers recommending lots of things that don't work. Pretty much anything, in fact. We can see the double-standard at play directly with the Ivermectin debate. Public masks and Ivermectin both have an evidence base of low-quality data, with weak effect sizes and huge error bars overall, and a clear bias of the strongest reported effect toward the lowest-quality evidence. But one is evil and the other is magic, depending on your politics.
To take it back to the subject of the OP, here we have two issues that are fundamentally nuanced (the evidence bases are ambigious, at best), and collapsing the range of allowable communication to "you must do X!" leads to obviously wrong outcomes no matter what you do. So maybe we shouldn't be doing anything at all? Or maybe...maybe...we could try to get answers with experiments, instead of just making things up and asserting that we're right?
For whatever it's worth, I recommend this paper as a balanced, comprehensive review of mask literature (not just cloth, though that is the title). You will not find a more complete treatment of the data for public masking:
To be clear, I'm not arguing that health care orgs should have recommended masks early in the pandemic. What I am saying is their adamant declarations of "masks don't work for the public", which note is an affirmative declaration, were false, and never had any supporting evidence. My question is about whether this "simpler, un-nuanced" explanation in fact complicated things in the longer run.
Yes, I know. We're basically in agreement on the broader points, but I don't agree with your second sentence, and you seem to have the opposite bias in terms of how to act under uncertainty:
> What I am saying is their adamant declarations of "masks don't work for the public", which note is an affirmative declaration, were false, and never had any supporting evidence.
There's no such thing as an affirmative declaration of the null hypothesis. You either have proof that something works, or you do not. If you do not have evidence that X works, or the evidence is ambiguous, your conclusion is the null hypothesis (that X doesn't work)...but that doesn't mean that you have to scream it from the rooftops. You can just say "we don't know; the evidence is poor."
The only accurate thing you can say in the "mask debate" is that strong declarations both ways are wrong. The original declarations were wrong, and the declarations now are also wrong. If you look at the data you can't judge either way (with the exception of cloth masks, which are looking quite poor), and so we must equivocate.
The only way you can possibly go on this issue and still be correct is to use nuance. And if you do that, then it's a question of how you use medical evidence to advocate for interventions.
> If you do not have evidence that X works, or the evidence is ambiguous, your conclusion is the null hypothesis (that X doesn't work)
No??? This is what having a prior is for. In this case, the prior was the mechanistic model which told you with reasonable confidence that masks would work in the slices of worlds where the primary mode of transmission was one mitigated by mask-wearing. We do not in fact live in a state of helplessness absent a double-blind peer-reviewed RCT; you will actively come to incorrect conclusions if you refuse to use your existing models & knowledge of the world to draw conclusions about the likelihoods of various outcomes.
> No??? This is what having a prior is for. In this case, the prior was the mechanistic model which told you with reasonable confidence that masks would work in the slices of worlds where the primary mode of transmission was one mitigated by mask-wearing.
Yes. I'm incorporating a prior. Read what I wrote at the top of the thread: every medical intervention that has ever failed a trial has had a biologically plausible justification for doing the trial. Nearly all trials fail.
In the history of medicine, literally every failed medication, surgery, treatment or intervention has had an explanation that seemed plausible at the time. Just as we're seeing with masks, the vast majority of interventions have little to no effect. Many make things worse. From bloodletting to thalidomide to failed cancer drugs, medicine is littered with examples of people who "knew" that their preferred treatment would work based on "priors" or "plausible mechanisms", and ended up doing great harm.
As a bayesian and someone who is knowledgable of science and medicine, my prior probability of any medical intervention working is almost zero.
> my prior probability of any medical intervention working is almost zero
Yes, this is reasonable, in the general case, absent a specific example to examine. However, masks do in fact work to prevent the spread of certain kinds of disease, based on both obvious mechanistic reasoning and on actual experimental evidence to that effect. Making the affirmative claim that masks would not work against covid (at the time) would have been ignoring or denying the non-trivial possibility that they would work quite well (or work poorly, but working poorly is still working on the margin).
> There's no such thing as an affirmative declaration of the null hypothesis.
I strongly disagree, epistemologically speaking. You can run repeated tests and then conclude an intervention is successful. You can also run repeated tests and conclude an intervention is not successful - as you put it, no better than the null hypothesis. Or, finally, you can have just not run tests at all. There is a difference between the second and third states, and health authorities implied the second state when the third state was far more accurate.
> You can also run repeated tests and conclude an intervention is not successful - as you put it, no better than the null hypothesis.
I don't disagree. You test to reject the null hypothesis. If you do not reject, you must accept. Eventually, hopefully, you give up on the failed alternative hypothesis and move on.
> Or, finally, you can have just not run tests at all. There is a difference between the second and third states, and health authorities implied the second state when the third state was far more accurate.
Early in the pandemic, virtually all the major health orgs spread the message "masks for the public don't work". Of course, the real issue was that there was a valid fear that there would be a run on masks and not enough for healthcare workers. There was never any significant evidence masks for the public don't work, on the contrary there was at least some flu-based evidenced that they were beneficial, but at best you could say "we don't know".
So I'm very sympathetic to the authorities trying to give simple messages, but in the end the original guidance really bit them in the ass and made a lot of people lose trust. I wonder if the simpler message could have been "don't use a mask, because it means nobody will be left to treat you when your nurse/doctor needs a mask".