19 thoughts on “A statistician’s rants and raves

  1. DF said:
    ‘So why do good numerate people worry more about my visiting Israel for the terror than for the autos? ‘

    I think most people judge themselves to be good drivers so that they think their risk of a car accident is lower than the average risk. Whereas terror attacks are pretty random and there are not a lot of ways to reduce your risk.

    • Isn’t the auto accident risk a baseline that is common to, say, the US and Israel (roughly the same). So his friends are indeed right to be worried and the reason is the *additional* risk of terrorist deaths. It’s not as if one risk was replaced by another; the second risk is an add on to the first.

      • The summary seems to say clearly that the risk per person-year of an auto death is about half as large in Israel than in the USA. One could argue that the correct measure is deaths/vehicle-mile-traveled, but that would probably be wrong, since simply being in a culture which requires less automobile travel makes you safer, ceteris paribus.

        If the total death rate in Israel from cars plus terrorism is less than the death rate in the US from cars plus terrorism, and all other risks are the same, then it is on average incorrect to worry that being in Israel is more dangerous than being in the US. The interesting point of Foster’s observation is probably that people systematically overestimate their ability to reduce their risks, and are much more bothered by things they perceive themselves as having no control over than things they think they can manage. Even if people can control some risks, and think that they will do so, in the end (tautologically) in aggregate they take an average amount of risk. And it is likely that while visitors can control the timing of their travel more than natives, that is more than offset by unfamiliarity with the roads.

        It’s basically the same problem in grasping reality that many people have when confronting the relative risks of travel modes – most people who worry about flying don’t give a second thought about the drive to the airport, even though that is the most dangerous part of the journey. People derive comfort, but not real safety, from their ability to delude themselves.

        Similarly, I often have to deal with concern from friends and relatives about my safety as a recreational cyclist out amidst a sea of SUVs driven by texting teens. I point out that while the risk of being injured or killed while exercising is real, there is also a (probably higher) risk of having a fatal heart attack while growing fat eating nachos on the couch watching all-star tiddlywinks on TV if I choose that “safer” leisure activity. Eventually I just point to the active promotion of “dangerous” cycling by combined insurance/medical providers like Group Health, and the fact that they have some at least minimally competent actuaries who have kept them solvent for a while. They care about their members’ risks, if for no other reason than greed. However, discussions about choices and risk are rarely contaminated with reason ……

        • You are right. I missed his last sentence about the relative car risks of Israel versus the US.

          OTOH, assuming I were travelling to Israel from a nation with comparable car-travel risk, then it ought to be legitimate to worry about terrorism?

        • It is always legitimate to worry about any risk, it is just more rational to put relative risks in perspective. If you were a westerner traveling to Israel from Afghanistan, then maybe you would take a break from worrying about terrorism. On the other hand, if you were traveling to Israel from Switzerland, then terrorism would would probably be an increased concern…

  2. I have a hard time believing Foster is serious about some of these. Take the one mpledger asks about above. There are plenty of things you can do to reduce your risk of dying in an auto accident. (Wear seatbelts, drive carefully, avoid driving when tired or conditions are bad, stay off the roads altogether, etc.) Many of these are especially easy for visitors, as opposed to those who live there and might be more or less forced to commute at set times no matter what the conditions. On the other hand, there is not so much you can do to control the risk of being blown up by terrorists, except avoid places where terrorists regularly set off bombs, a set of which Israel is, sadly, a prominent member. Now you might decide that ignoring that risk is the right thing to do, but it is not crazy for Foster’s numerate friends to worry more about the uncontrollable danger than the controllable one.

  3. Some of these are good (and the Israel one is not good, but not at all for the reasons given by the earlier commenters…and it would be easy to fix).

    But I hate to see Bjorn Lomborg get any kind of hat tip, since he usually sets up straw men and then proudly batters them, often in a way that obfuscates rather than clarifying, and that is the case here too. For one thing, although there may be people who eat organic produce purely because the think it has less cancer risk I have never met anyone who says that is their only reason (and, living in Berkeley, I have spoken with a lot of people who eat organic produce). Other reasons cited include supporting small farms, less bad for the environment, and better taste. Second, I doubt people who eat organic produce feed their kids less of it than of they bought conventional produce. Which one ate you more likely to allow to expire without using it, a theater ticket that cost you $5 or one that cost you $20?

    • Phil, I think the point is not that people let the food go bad, but that they buy say 1900 lbs of produce a year instead of 2000 or something like that, just a little bit of economizing. It’s almost certainly the case that people who buy organic only buy less than those who buy non-organic. The price difference is noticeable and the whole point of prices is that they’re a signal to economize.

      • It isn’t as if people have a fixed, specific food budget. Maybe the extra dollar they spend on organic apples gets compensated by the one less dollar they spend on, say, movies?

      • Phil was just pointing out that the increased desire not to waste something more expensive might mitigate the tendency to buy less of something more expensive. I don’t know to what degree this happens in practice. I think the real problem with the Lomborg claim is that it reeks of overinterpreting a regression coefficient.

        • Zach, yes, that was one thing I was pointing out. People could conceivably buy less but eat the same amount. Something like 1/4 of the food purchased in the U.S. is discarded uneaten, which suggests a large capacity to buy less without eating less.

          But my other point, which I did not make sufficiently clear, is that Lomborg talks as though this is the mistaken thought process people go through when deciding to buy organic food: “Organic food is better for me and my kids, therefore I will pay more and buy organic food.” Although there may be some people who think that way, that is not the only reasoning for people who buy organic food. My own reason is more like “Organic food is no worse for me than conventional food, and it’s much better for the environment as a whole and for the agricultural workers who produce it. Therefore I will pay more and buy organic food.” I don’t think I’m healthier for it, and yet I buy it anyway. Lomborg seems to think people like me don’t exist.

  4. The most annoying thing was the high density of broken / dead links on that site! It was like teasers without any chance of getting the full story.

    • Sorry about the dead links. I haven’t clicked on them in ages–so I didn’t know so many had died. I’ve started going through them again and have found modern replacments for most of them. The “Rants” section is hopefully clean now. I’ll work on the “raves” section next.

  5. FTA: A great rant from Bjorn Lomborg: “If you reduce your child’s intake of fruits and vegetables by just 0.03 grams a day (that’s the equivalent of half a grain of rice) when you opt for more expensive organic produce, the total risk of cancer goes up, not down. Omit buying just one apple every 20 years because you have gone organic, and your child is worse off.”

    That just shows how selfish Bjorn Lomborg is: All he cares about is his *own* child.

    • David:

      1. I don’t think Lomborg is talking about his own child. He’s giving general advice, which implies to me that he’s talking about other people’s children.

      2. I’m curious abut Lomborg’s numbers. They seem too extreme to be plausible. I guess this deserves a separate post.

  6. Pingback: Confusion from illusory precision « Statistical Modeling, Causal Inference, and Social Science

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