[jld]

Double blind studies are helpful when we do not understand they underlying dynamics of a complicated system (like a body) but we want to learn what effect a change has on that system (like a medicine).

If we know pathogens cause disease, and we know filtering removes pathogens from the air (and we can test and verify that) we don't need to run a double blind study to verify they work.

It's the same reason you don't need to run a double blind study on whether seat belts work. We understand the cause and effect of car ejections and windshield/steering wheel impacts on human bodies. Seat belts are designed to mitigate these incidents and are tested and validated in the lab using formal science and engineering.

[valbaca]

> It's the same reason you don't need to run a double blind study on whether seat belts work.

We might need some historical investigation into the road that was travelled to get seatbelts to where they are now (physically, legally, and socially). I'm a millennial and I remember growing up where similar arguments were made:

- "If it's my time to go, then it's God's will"

- "It's uncomfortable"

- zero/inconsistent law enforcement

- "If the car rolls over than it can trap you"

To now, where it's entirely automatic and incredibly wild to even suggest being without a seatbelt.

[astura]

Its crazy, I was born in the early 80s and I never wore a seatbelt until I started driving. As a kid I would ride in a van that didn't even have seats and think absolutely nothing of it.

[rootusrootus]

I was born in the early 70s and we always wore seatbelts, for as long as I can remember. Though we did routinely ride in the back of the pickup, which isn't something I see happening much today.

[c0nsumer]

Don't forget the one about how it's safer to be thrown free of a wreck (which will happen if you don't wear your seatbelt) than remain in the car. <sigh>

[closeparen]

You're not going to spend 100% of your day in the coverage of one of these things, so what's the dose response? How many hours per day of filtered air equals how many fewer infections per year? Does air filtration in your workplace matter at all if you have young kids in school? Does air filtration in a school matter at all if the kids are all together on a poorly ventilated bus for two hours a day?

Seems like some evidence would be helpful.

[schiffern]

Yes we have studied actual rates of infection in response to interventions like air filtering, so these studies account for all that real-world complexity and messiness you worry about.

The article is complaining that every study doesn't redo the evidence collection, end-to-end, every time. That's not realistic and not necessary.

A lot of your specific questions are leading (with a nothing-we-can-do attitude underneath) or asking the wrong question (eg expecting one universal number for "hours of filtration per infection prevented").

For instance the correct answer may be air filters in classrooms and buses and workplaces, but strangely your line of questioning doesn't even consider that possibility.

This would be like someone in the 1800s questioning how handwashing avoids Cholera if they don't wash their hands at home. I think I see a solution to this one...

[wahnfrieden]

Kids don’t transmit tire and brake dust into my lungs

[slyzmud]

> It's the same reason you don't need to run a double blind study on whether seat belts work

Actually, seat belts are a weird example. After they were invented, there were more car crashes since people trusted they were protected. Without seat belts people were more cautious. They were a net positive of course, but some different situations/inventions/studies might have effects that are the opposite of what you would expect.

[fanf2]

That’s a myth https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1540-6237....