Great, Pithy Quote About How We Get the Numbers Wrong

Granted, this quote is about a competely different topic — one I don’t even want to discuss here:  swine flu. BUT this observation by Professor Dirk Brockmann, who models epidemics, holds so true for so MANY  fears, I just had to to shout it out. Here he is, as quoted in today’s New York Times:

“People have a very weird perception of large numbers. If you have 2,000 cases of flu in a country of 300 million, most people think they’re going to be one of the 2,000, not one of the 299,998,000.”

That is just how our minds seem to work. And it goes double for our fears for our kids. It’s nice to be reminded, sometimes, how very off our perceptions (and worries) can be.  — Lenore  

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22 Responses

  1. How very true!

  2. I don’t quite see the point of this argument. If 50,000 people die in car accidents every year, does it make sense to visualize yourself as one of the 50,000, or one of the 299,950,000 ? So why wear a seat belt?

    It’s true that our perceptions of danger are greatly distorted, principally by a media culture which loves to focus on weird new hazards and ignore routine ones, but this kind of statistical analysis by itself doesn’t really help.

    Protecting oneself against hazards has to take into account (a) the likelihood of the hazard; (b) the severity of the consequences of that hazard; and (c) the cost (or side effects) of the preventive measures. You’ve done an excellent job on this website of arguing that we should give greater weight to (c) when making choices about our children. Wearing a seat belt is a small price to pay for protection against car accident hazard. Life in a bubble is too high a price for a child to be protected against low-risk hazards like child abduction. But the high price is a stronger argument than the prevalance of the hazard.

  3. Lenore, I’m a big fan of your going back a couple of years to your subway column. I blogged about your Salon interview today on my site. Check it out!

    http://kareneklein.blogspot.com/2009/05/free-range-kids.html

  4. I will play the devil’s advocate here and remind you that, unlike the predator threat, which is miniscule, the threat of a world-wide flu pandemic, from the numbers we were seeing in Mexico, was (and remains) very high.

    I don’t think that taking some basic cautionary measures, like handwashing and being vigilant about not sharing germs, is a really bad idea.

    Not panic, of course, which is another really bad idea.

  5. Of course it makes sense to see yourself as one of the 299,950,000 who will NOT die in a car accident. If you saw yourself as one of the 50,000, you wouldn’t be able to drive a car safely because of the fear that this time might be it. You wouldn’t be able to ride in a car without undue stress. It also makes sense to take common sense precautions to avoid being one of the 50,000. So you wear a seat belt, use your turn signals and headlights, etc. Do those things guarantee your safety? Nope, but they make you more like to be safe and they allow you to live without undue fear. It also makes sense to wash your hands regularly to avoid the spread of unhealthy germs. Because you’d like to stay in the big number. And the more people who use common sense and courtesy in their behavior in hygiene there are, the bigger the big number will get. Finally, because this is free-range kids, it makes sense to take normal, common sense precautions with your kids to keep them in the larger, unmolested number. It does not make sense to keep them locked up, teaching them fear and dependence anymore than it would make sense for you to walk everywhere because you’re sure that you’re in the 50,000 people who are doomed to die if they get in a car accident.

  6. Interesting that a hundred odd people die because of swine flu and it becomes and world wide pandemic!! Everyone needs to panic and buy masks and “specific flu medicine”. (Or so the media leads us to believe.)

    Meanwhile 3000 people die PER DAY of malaria and it is a “health problem” that doesn’t get any mention in any news.

    This is because, I think, there is no money to be made with the malaria problem. And this “swine flu pandemic” is a perfect solution to getting people’s focus off of the pillaging that is happening by governments in the global financial crisis. Our children’s children’s children are going to be paying back these “bailouts” for years to come.

    Anyone remember the hyped panic with SARS and avian flu that ended up being nothing major in the end… ??

  7. It’s called the “availability heuristic” (http://en.wikipedia.org/wiki/Availability_heuristic) people think it because the newpapers don’t run stories saying “Man is New York is healthy” So when people try to assess the likelihood of something happen they think about situations they’ve heard about. They’ve heard of a lot of people having it, but not a lot about people not having it so logic is disregarded.

  8. @ The Mother:

    The numbers in Mexico didn’t even top 150 cases for swine flu… not sure what hyped up news program gave something bigger, but it was certainly not anything close to pandemic. In fact, last I heard, there were about 18 fatalities due to the swine flu. Hardly anything when you consider that number is the total from the entire world – not just Mexico.

    @ wahoofive:

    I think the idea of the post isn’t to show a statistical analysis, but to show that people don’t *bother* to think statistically.

    Of course, per your example, you always want to buckle up and take reasonable precautions (reasonable being the operative word), but people anymore hear a number and go into frenzy mode (ala swine flu “pandemic”), thinking they have to protect themselves at all costs from the small chance of harm.

    Who is to say, until studies are done, that swine flu wouldn’t have been MUCH worse if all those people hadn’t run out like mad and bought up medications and masks and so forth? We don’t know, but if we rationalize everything that way, life really isn’t going to be much worth living since everything will ring of Chicken Little’s sky falling.

  9. Greetings from the land of Drug Lords and The Swine Flu. As with any flu, the very young, the very old and the immunosuppressed need to be concerned about this virus strain. We have had three confirmed cases in the state of Qintana Roo and all three are responding well to medication. Life continues on as usual here. The only panic seemes to be on the TV broadcast to us from the US and Canada. People are being cautious and practicing good hygene but otherwise going on with their everyday lives and responsibilities. The chances of us contracting this or any other virus are about the same as encountering drug cartel activity: very low.
    This concludes your Free Range expat report from Mexico.😉

  10. We’re using this “pandemic” in our house as a springboard for some great discussions about relative risk, and what steps are worth taking to prevent risk. Common sense – hand-washing and avoiding people who appear to be really sick – is a fine response. We’ve solemnly promised, if masks become vogue, we’ll each get some with big, cartoonish happy faces on them. If we’re going to be silly, be silly on purpose.

    Likewise, it makes the best sense to take sensible precautions with safety, like not jumping off roofs, learning basic self-defense, and being aware of your surroundings. It’s not worth the cost to avoid all people for fear of the one who might be dangerous.

    That said, I’m not sure that all the precautions are necessarily bad. I think the government is struggling to figure out how much information to disseminate and what level of precaution is good. We tend to think of SARS and bird flu, but we forget that the last pandemic to hit was actually HIV. THAT one continues to be a fairly serious problem. When we’ve got an unknown bug on the loose in the early stages, it doesn’t make sense on an individual level to worry much. It does make sense on epidemiological scales to aggressively control the spread until we know what the thing does, and what we can do about it. If swine flu had been more difficult to control, with a higher mortality rate, the stories today would have been a lot different. As is, I suspect there are at minimum 10 cases for every one we hear about – just because for flu symptoms, not everyone is going to go rushing to the doctor, and not every doctor is going to bother collecting a culture. Still, it’s low-risk it seems, and I’m not inclined to worry. I think we’ve even got enough baseline to quit closing schools and otherwise aggressively controling the spread.

  11. I’ve written numerous times over the years on my blog about how bad the human brain is at handling probability and risk. It’s true with air vs. car travel, with terrorism, with climate change, with vaccinations, with lottery tickets, and on and on.

    Yesterday your recent interview and posts here became a source of discussion there again. I agree that kids are safe and should be outside, and while my daughters have been walking themselves to school for awhile now, my wife and I are still working on giving them the freedom to visit friends and explore the neighbourhood. I’m ranting against my own paranoia, and trying to be more rational, too.

  12. I’m counting on the news folk to drag out this flu drama for a couple more weeks before switching to the really exciting alarming news that it’s hurricane season and we may, gasp, have some bad weather! More predictions, more urging of caution, more panic mongering and on it goes. *sigh* I avoid televised news as much as possible. When you read the news from a print medium, it’s slightly less stressful.

  13. I couldn’t agree with you more. We’ve gone nuts protecting our kids. When I was 7 I was home for the summer with two older brothers, and allowed to ride my bike about 1 mile to the local pool and swim all day ALONE. (sound bizarre now, but I did it). What did I learn? Responsibility, independence and self control. Today my parents would be considered irresponsible, but they are terrific, and raised 3 outstanding kids who all own their own businesses. We are all independent and capable.

    Your voice is the pendelum we have needed for a long time. While there are still kids running amok in some of our neighborhoods, (I’m a realtor, so I see it) many responsible parents are not allowing their kids to develop independence and self-controlled thinking by giving them a little freedom. It’s so dang rare for there to be an abduction, yet we run our lives as if it happens every day. Come on!

    I have felt exactly as you, but have not had the courage to take the public smackdown for me stance. You go, girl.

  14. Here’s how the Swine Flu almost affected Free Ranging kids at one school: The school board and district decided to cancel *all* field trips (including some that the kids found ways to raise money to go on), all after school gatherings (including a talent show that the kids themselves make up the acts for), and all promotion ceremonies (including kindergarten graduation–and my last of three kids is in kindergarten). Some of us parents fought for our kids because the consequences from the school district and board’s decision to error on the side of paranoia was too extreme. What finally got the district to reconsider was a sensible county health director who saw that schools were overreacting.

  15. When they cancel school for Swine Flu, where are the kids supposed to go? The mall? Overcrowded daycare? Work with mom or dad? How is that supposed to protect them?

    If you really get an epidemic actually happening in a local area, then it makes sense to close the schools, because then people will take it seriously enough to keep their kids home, and stay home. That happens in some places in years when the seasonal flu is especially bad. But if they’re canceling school in a place where there isn’t a reasonable danger of spreading a disease that ONE PERSON IN TOWN, who is at home in bed anyway has, that’s not going to do a bit of good.

  16. Yeah, until you are the mother of a daughter who happens to be one of the 300 cases of Diffused Pontine Glioma (brain tumor) diagnosed yearly in the United States…and it kills her.

    Then you realize those numbers could indeed be yours as quickly as anyone else’s.

  17. And, won? I’m sorry for your loss, but what’s the point? If you spend your life worrying about this and that and risks that are so tiny as to be virtually non-existent (and your daughter had literally a one in a million chance of getting that tumor. LESS than that) you don’t have time to live your life. You can’t live like that, you can barely even survive like that.

  18. Any of us could die anytime. I have cancer, so my chances are greater than most (I tell people that anyone can get hit by a bus, but I’m dodging buses all the time). But we can’t expect death around every corner — or we’d become either paralyzed or reckless.

  19. This is so true. I’ve delayed vaccinating my toddler until her second birthday (for my own bad-at-math emotional reasons: because I know two people whose babies were killed or crippled due to infant vaccine reactions, and no one who has ever had a vaccine-preventable disease).

    I have a number of pregnant friends, and the other day we were all out for ice cream. One of my pregnant friends was sharing her ice cream cone with my toddler when the other pregnant friend said, “I won’t share food with that baby because she hasn’t been vaccinated for rubella.” The first woman had a moment of panic and both women began avoiding the baby.

    My husband and I were curious: what are the odds that our kid could be an invisible carrier for rubella?

    The answer: about 1 in a billion. Yet the pregnant mamas who avoided her are just doing what their health care providers told them to. It’s another case where a dramatic but incredibly unlikely bad effect draws more attention and efforts at prevention than a real but prosaic risk.

  20. Sierra: The reason the odds of your kid being a rubella carrier are so low is because almost everybody else vaccinates their kids, so there are few people he could pick it up from. But if everybody did as you did, the odds would be a whole lot higher. You’re relying on “herd immunity.”

  21. My family came down with colds right in the middle of this whole swine flu thing. I immediately had people asking if I thought it might be swine flu. My answer was a rather obvious no. The odds were against it, and there wasn’t the sort of symptoms one would really expect for any flu.

    Considering that swine flu now looks to be no more dangerous than regular flu, that’s about how much I’ll worry about it until proven otherwise. Something to be avoided through standard precautions, but not terrifying.

  22. They(the media) has been pushing swine flu as fear. More people got tuberculosis and died. If you look back in the 70’s more people died for the vaccine for the swine flu than the flu itself. For the most part as long as we eat “healthy” our bodies will take care of most issues it encounters.

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