3 ms·

With a new and developing situation like COVID, where the unknowns are more than the knowns, being more safe may mean being less evidence-first, and being evide

With a new and developing situation like COVID, where the unknowns are more than the knowns, being more safe may mean being less evidence-first, and being evidence-first may mean being less safe. The advice was against wearing masks for so long because even though wearing masks was the cautious thing to do, it was not what the evidence suggested. If we wanted to go by evidence alone, there probably would be an advisory even today saying "there is no evidence masks work. I guess you can wear it as a fashion statement, but we have no evidence it would help with preventing the spread. You definitely shouldn't force shoppers, workers, travellers, etc. wear one, because evidence does not show it is required or even helpful."

ngcc_hk 6y ago
I think the evidence is so far NOT to protect you (might be a bit) but to protect AGAINST you. Hence the advise so far is if you have the sickness you should. Otherwise ... which is the BAD advise by who. From a public health and human dynamics point of view. The key issue is that you do not know you have it. And asking people to protect others as the main theme does not work. The full mask on is important as it eliminates the incentive of not having the inconvenices. And stop the spread. For work environment it is a risk and they should have some always on. Otherwise it will spread. In fact if one not on and start, the mask is the best collector of gems.
- cma 6y ago
  It protects others more against you for you to wear one than for them (e.g. in dry conditions a droplet can evaporate into one that is more of a hanging aerosol by the time it gets to their mask where it could have been stopped by yours).
bdamm 6y ago
You only have to sit across the table from an exuberant interlocutor to understand that masks help slow the spread of viruses. Surely everyone has noticed that people spit when they talk. That studies have a difficulty capturing that has more to do with how difficult good social behavior studies are.
perl4ever 6y ago
Apologies to those who have seen this before: "Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/
- bavell 6y ago
  This treasure trove contains gems like, "medical interventions based solely on observational data should be carefully scrutinised, and the parachute is no exception." and "The parachute industry has earned billions of dollars for vast multinational corporations whose profits depend on belief in the efficacy of their product."
- SilasX 6y ago
  Yes! And also, I would advocate reading Slate Star Codex's "A Failure, but Not of Prediction"[1] as a follow-up, which sort of resolves the "parachute paradox" of why you should believe in the efficacy of parachutes for skydiving in the absence of RCTs, and when you should require them for a belief. I summarized the heuristic in that discussion [2]. In the case of parachutes, that heuristic would (lead you to) say that, we know (from RCTs) that parachutes slow the fall of objects, we know humans suffer greater injury the faster they hit the ground, and parachutes are inexpensive relative to the potential risk, therefore you should believe they work in the absence of an RCT. [1] https://slatestarcodex.com/2020/04/14/a-failure-but-not-of-prediction/ https://slatestarcodex.com/2020/04/14/a-failure-but-not-of-p... [2] https://news.ycombinator.com/item?id=22908365 https://news.ycombinator.com/item?id=22908365

ngcc_hk 6y ago

I think the evidence is so far NOT to protect you (might be a bit) but to protect AGAINST you. Hence the advise so far is if you have the sickness you should. Otherwise ... which is the BAD advise by who. From a public health and human dynamics point of view. The key issue is that you do not know you have it. And asking people to protect others as the main theme does not work. The full mask on is important as it eliminates the incentive of not having the inconvenices. And stop the spread. For work environment it is a risk and they should have some always on. Otherwise it will spread. In fact if one not on and start, the mask is the best collector of gems.

cma 6y ago
It protects others more against you for you to wear one than for them (e.g. in dry conditions a droplet can evaporate into one that is more of a hanging aerosol by the time it gets to their mask where it could have been stopped by yours).

bdamm 6y ago

You only have to sit across the table from an exuberant interlocutor to understand that masks help slow the spread of viruses. Surely everyone has noticed that people spit when they talk. That studies have a difficulty capturing that has more to do with how difficult good social behavior studies are.

perl4ever 6y ago

Apologies to those who have seen this before: "Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/

bavell 6y ago
This treasure trove contains gems like, "medical interventions based solely on observational data should be carefully scrutinised, and the parachute is no exception." and "The parachute industry has earned billions of dollars for vast multinational corporations whose profits depend on belief in the efficacy of their product."
SilasX 6y ago
Yes! And also, I would advocate reading Slate Star Codex's "A Failure, but Not of Prediction"[1] as a follow-up, which sort of resolves the "parachute paradox" of why you should believe in the efficacy of parachutes for skydiving in the absence of RCTs, and when you should require them for a belief. I summarized the heuristic in that discussion [2]. In the case of parachutes, that heuristic would (lead you to) say that, we know (from RCTs) that parachutes slow the fall of objects, we know humans suffer greater injury the faster they hit the ground, and parachutes are inexpensive relative to the potential risk, therefore you should believe they work in the absence of an RCT. [1] https://slatestarcodex.com/2020/04/14/a-failure-but-not-of-prediction/ https://slatestarcodex.com/2020/04/14/a-failure-but-not-of-p... [2] https://news.ycombinator.com/item?id=22908365 https://news.ycombinator.com/item?id=22908365