Video: Rebecca Watson on mask science (they work!)

Both Tegan and I decided to start masking early on in the pandemic, well before anyone was requiring it. Sometimes, it was something close to useless like a bandanna, but since Tegan had a customer service job in Glasgow, she made herself a couple multi-layer masks, and I eventually bought a neck gaiter with disposable filter inserts. I’ve always viewed the mask question from something of a gamer’s perspective on odds. Back when I was an avid World of Warcraft player, I had to pay close attention to cumulative percentages. Any one piece of gear, while helpful, wasn’t as useful as all of it together, whether it came to your chance of landing a critical strike, or your chance of blocking or dodging an enemy’s attack.

I don’t expect the vaccine to protect me entirely, just to improve my odds. Masks are the same – they might only stop a small percent of particles I’d otherwise inhale, but that still improves my odds of staying healthy. I wouldn’t expect my masks to do anything to stop the fine particulate air pollution I’ve mentioned in the past, but yeah – they provide one very imperfect physical barrier between myself in the world. How could it not be better than nothing? After the last couple years, it just feels like common courtesy to mask.

Still, some people adamantly oppose masking, and will insist that the science shows no clear benefit. Obviously I disagree, but I think it’s fair to be doubtful, especially with so many contradictory messages out there. Rebecca Watson takes on that uncertainty, and a recent report on the efficacy of masks. The TL:DR is that masks do help with COVID, at least a little, but also that the people who put the report together did so in such a way as to give the impression that they don’t.

As always, you can find the video’s transcript and sources on Skepchick, but I just wanted to highlight one thing:

“But wait,” you may be saying, “my MAGA uncle says that Cochrane Review says masks don’t work. What’s going on?”


The review is titled “Physical interventions to interrupt or reduce the spread of respiratory viruses,” and it is available in full online and as always I link to all my sources in the transcript which you can find linked below or at This review did conclude that “Wearing masks in the community probably makes little or no difference to the outcome of influenza-like illness/COVID-19 like illness compared to not wearing masks.”

Immediately, you might note that this is about “respiratory viruses,” and not specifically COVID-19. That’s important, because they lumped in a few studies on the effectiveness of masks versus COVID along with a whole bunch of studies on non-epidemic influenza, which is way less contagious and rarer to contract, meaning that of course you’re going to need way more data to show any result, compared to looking at masks in the middle of the COVID-19 pandemic.

In fact, epidemiologist Gideon Meyerowitz-Katz decided to remove the data for influenza to see what would happen, and sure enough, the random controlled trials for masking DURING A PANDEMIC showed a clear, modest benefit. He points out that the review is perfectly fine otherwise, but personally I think it’s a pretty big deal that Cochrane released this during a pandemic, knowing that people would assume that the conclusion would be applied during a pandemic. It’s like releasing a review concluding there’s no benefit to wearing a seat belt, without mentioning that most of the data I examined was from a survey of people sitting in parked cars in the grocery store parking lot. It turns out that context is very important!

This frustrates me. Scientists ought to know how important context is, and I find it hard to believe that they don’t know how much confusion there is on this particular topic. I suppose I’ll never know for sure whether the way they structured their report was deliberate, but I feel like the responsible thing to do would have been to write a paper that wouldn’t create this kind of confusion. Still, it’s nice to have a bit more support for my position. As I said before, I think masking in indoor public spaces is just a matter of courtesy.

Now, I’m not always the most courteous guy – sometimes I forget a mask when I go out, or I don’t have one that’s clean. I also eat at restaurants on rare occasions, and if you’re in some form of eatery, wearing a mask seems a bit like spitting in the wind. I’m also aware that my opinion on “common” courtesy isn’t particularly common – the vast majority of folks in Dublin don’t wear masks anymore, and based on the consistently low COVID numbers, that doesn’t seem to be doing a whole lot of harm. It helps that we’ve got a pretty high vaccination rate. The Kraken may have originated here, but it didn’t turn out to be much of a monster.

Masks work, in that they improve your odds. That’s a limited and uncertain benefit, but the reality is that we are beset by uncertainties at every moment in our lives. Accepting that is – or ought to be – a natural process of growing up and maturing, but obviously it’s not a comfortable process, and most people are trained, to some degree, to reject uncertainty. The distressing truth is that this world is messy and complicated, and sometimes when you’re dealing with a mess, it’s better to just wear a mask.


  1. dangerousbeans says

    I don’t know about Ireland, but here in Australia reported case data is basically useless due to under reporting. I’ve been keeping track of hospitalisations, but that only tells you about serious cases and vaccines are quite good at preventing them.
    Since I don’t want it again I’m still masking and not being frivolous about going places

  2. marner says

    Thank you for writing this. It definitely deserves comment. I found this interview with one of the reviews lead authors interesting
    One of his answers:

    There’s no evidence that they do work, that’s right. It’s possible they could work in some settings….we’d know if we’d done trials.

    Regardless, I don’t think Ms. Watson makes a compelling argument (which doesn’t mean that she isn’t correct). I especially dislike her poisonings of the well by comparing doubters to January 6th stormers of the castle.

    As an aside, I had been expecting more comment on this after it came out on January 30th. Now that the New York Times has opined, it seems to be trending. The “Grey Lady effect” appears to still be true. Which is both fascinating and scary.

  3. says

    The “Grey Lady effect” appears to still be true. Which is both fascinating and scary.

    You’d think they’d have burned their credibility by now, but all that really matters is how the aristocracy feels about them.

  4. lochaber says

    I’ve also thought of COVID transmission reduction methods as a probability thing, and I think a lot of the people who sincerely believe “masks don’t work” (as opposed to all those simply being contrarian assholes), are thinking of it as a binary thing – they will almost always have some anecdote about someone who wore a mask, and still got COVID, (or, conversely, someone who never wore a mask, and never got sick…), and it’s almost impossible to get them to understand that COVID transmission isn’t a single event, like a lightning strike, but countless, constant interactions with tiny little microdroplets, some of which may contain COVID, some may not. some may get inhaled, some get caught in the fabric of a mask, some pass through, etc., etc.

    And then, I feel that a lot of it had to do with how people could be classified into “selfish” or “community minded”, especially early in the pandemic, when masks were thought to only/primarily protect other people from the one wearing the mask. So around me, most people I knew were mostly wearing masks to protect other people, and thought of preventing disease transmission as a group effort type of thing. The other people, well, they are like what’s being talked about in PZ’s post about paper towel waste…

    I’ve been a bit lax about personal precautions. I’ve probably got a bit of overconfidence in my immune system (I’ve never gotten the flu), but I still wear a cloth mask when going out, and earlier was even wearing a mask during my ~12 mile bicycle commute (it’s not that much of a hardship, toughguys…)

    Just looking at how we’ve completely failed as a collective society to handle (what should have been a minor) pandemic, has really caused me to doubt we will ever do anything about climate change, corporate greed, or any number of other problems that each individually have the ability to destroy human civilization.

    I feel like I’m sitting in a hut as winter is starting, and the others are eating seed corn for a midnight snack, and pulling insulation out of the walls and burning it because their sweater is too itchy.

  5. John Morales says

    Faint praise.

    … sometimes when you’re dealing with a mess, it’s better to just wear a mask.

    This is equivalent to “sometimes when you’re dealing with a mess, it’s not better to wear a mask.”


    Just looking at how we’ve completely failed as a collective society to handle (what should have been a minor) pandemic […]

    Um, this complete failure, as you characterise it, has resulted in continuing on as a collective society.

    (Surely not continuing on would be even more complete a failure, no?)

  6. Dunc says

    Another interesting point is that they compared medical/surgical masks versus no masks, and N95/P2 respirators versus medical/surgical masks, but not N95/P2 respirators versus no masks. It’s entirely possible that they would have found clearer evidence of effectiveness had they done so.

    In the situations where I’m still masking (mostly on public transport), I’ve been wearing an N95 respirator (with an additional nose-piece to improve fit) since the emergence of the Omicron variant.

    Also worth noting: ” Adherence with interventions was low in many studies.” In other words: we asked people in the test group to wear masks, but they often didn’t bother, and then we didn’t find much difference between the test and control groups.

  7. says

    Um, this complete failure, as you characterise it, has resulted in continuing on as a collective society.

    (Surely not continuing on would be even more complete a failure, no?)

    That’s a pointlessly low bar. There seems to be zero question that the response could have been better, and saved tens, or even hundreds of thousands of lives in “western” countries, particularly the U.S., not to mention the problem of long COVID, which we’re still trying to figure out. COVID was never going to kill everybody and end society, so talking about that as the boundary for “complete failure” seems a bit odd.

    This is equivalent to “sometimes when you’re dealing with a mess, it’s not better to wear a mask.”

    This is a rhetorical flourish to wrap up a piece of writing.

  8. Jerome says

    Your point on probability is on point. If it turned out to be the case that N95’s only gave you a 5% reduced probability of catching COVID during some time interval where you’re subjected to exposure…. then I would still wear the mask! Why wouldn’t somebody do something so easy for a measurable benefit? Anything that isn’t 0% is worth doing, if the time and effort to do it is negligible. There’s no need to demand 100% protection to be motivated to do something.

    Because I think the heart of the issue is that a lot of casual anti-maskers (as in the people who aren’t crazy but just don’t really care anymore) have convinced themselves that wearing a mask is somehow an inconvenience, but it isn’t at all. They act like it’s a hassle, and say they don’t bother, implying that wearing a mask takes effort and has some kind of downside. If you’re walking into a store for 10 minutes, I can’t even comprehend the idea of complaining about it.

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