[JoeAltmaier]

Because population density and culture are the other factors. In most cases, combined with limiting large groups and reducing the frequency of meetings, it is doing what it is intended to do - reduce the R0 factor. Even in LA.

Every Internet pundit who can take one number and divide by another, announces they have proven something or other. Give it a rest.

[irq11]

There’s always an excuse, but there’s never any data backing your claims.

Provide even a single shred of evidence that masks affect the R0 of the virus in the real world.

Modeling studies and correlations observed in April don’t count: most of the papers published this year looked at areas where case counts subsequently skyrocketed in the fall. My personal favorite is the mask study from Jena, Germany in the spring, which only made it into a journal right as cases were reaching an all-time high in the same area:

https://www.pnas.org/content/early/2020/12/02/2015954117

https://gesundheit.jena.de/en/coronavirus

[jiofih]

From the first link you mention:

> we conclude that 20 d after becoming mandatory face masks have reduced the number of new infections by around 45%

A later increase in infections does not invalidate statistical significance for earlier studies. It’s just math, not “an excuse”. You’ll never see the data for how many cases would have been recorded without the measures in place.

You can see the full paper here: http://ftp.iza.org/dp13319.pdf

The second link you posted earlier also says conclusively that higher reported mask usage correlated with lower reports of symptoms. Are you even reading your own sources?

Or maybe you just have very skewed expectations of the impact? The Jena study estimates a 0.23 reduction in R rate. It is nowhere close to eliminating the disease, but this small reduction in transmission rate has an outsized effect on the total number of cases, hospitalizations and deaths, and that is what really matters (roughly, a 50% increase in transmission would result in 10x more deaths).

The inconvenience of wearing a mask is an insignificant price to pay even if the numbers are off by an order of magnitude.

[irq11]

> A later increase in infections does not invalidate statistical significance for earlier studies. It’s just math, not “an excuse”.

So your theory is that masks worked then, but stopped working now?

Convenient!

> You’ll never see the data for how many cases would have been recorded without the measures in place.

Well, yes, exactly...these are uncontrolled studies. Which is why they’re such garbage.

You can see that in the title of the paper you posted: “a synthetic control study”. That means they didn’t have a control. Which means all they can do is squint at correlations and try to claim they prove cause.

(oh also: the WaPo “data” is from a phone survey...so yeah: people who say they wear masks a lot claim they have fewer “symptoms”. Whatever that means.)

[joshuamorton]

> So your theory is that masks worked then, but stopped working now?

This doesn't follow. It's completely believable that masks have continued to be effective at curbing spread by 40% continuously. However increased holiday travel, as well as colder weather and people hanging out more in doors caused an increase in spread that wasn't present in the summer.

[irq11]

So let me summarize:

Cases go down after mask mandate: proof that masks work!

Cases go up after mask mandate: masks still work!

This isn’t science.

[joshuamorton]

You're right, your inference method isn't science. Science is "given two relatively similar municipalities, if one enforces a mask mandate, cases decrease in that municipality compared to the other". A finding that was repeatedly verified on the scale of cities, counties, and nations.

That months after mask mandates were enforced, case rates went up everywhere, including in places where masks weren't enforced, doesn't sound like it has particularly much to do with masks.

[JoeAltmaier]

What isn't science, is every internet genius that can divide one number by another, or compare two numbers but ignore everything about the context, is suddenly a self-proclaimed expert.

Here's a notion. Listen to real experts, and do what they advise. Instead of spinning yourself up and posting nonsense.

[jiofih]

No, the one from Jena was a controlled study, and they tried to exclude any biases like neighboring cities. It’s “synthetic” because you can’t create two equal cities and population to test, unfortunately.

Again, did you actually open and read the link? It’s pointless to discuss your feelings in place of the studies. You’re dismissing all of the data in that report based on.. what? Again, the increase in total cases tells you nothing about the efficacy of the measures. The controlled study does that.

Studies like these can be invalidated by further studies, or systematic reviews. They are not invalidated by popular feelings over news reports. Show me one of those statistically-backed rebuttals and I’ll believe you.

(The WaPo link was posted by yourself, most of those are self-reported. It’s good that you notice because it also weakens your own argument if you think about it)

[irq11]

It’s a “synthetic control” because they didn’t actually have a control group. So they tried to pretend their was such a group by taking data from elsewhere.

Yes, I read the paper.

[jiofih]

How else do you propose a control group for an entire city, other than looking at other cities in the same region? Have you done research like this before?

[pmiller2]

Here you go: https://www.nature.com/articles/d41586-020-02801-8

Read that, chase down all the study links therein, and come back a week after you've found out you're wrong.