My own thoughts--for me.
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Saturday, April 17, 2004

No Fear (Hardly) 

I know you're worried about me. There's no need, really. I hope I convinced you that the risks of flying to Israel are tiny. Of course, there's still the risk on the ground, with all the news of suicide bombings. Some say Jerusalem is a dangerous place. It's probably true that no other city outside Baghdad poses as great a risk of suicide bombers. If you're primary goal in life is to avoid being the victim of a suicide bomber, then you might be wiser to choose another destination. But does that make it dangerous? No states poses as great a risk of tornadoes as Oklahoma and Texas. Does that make them dangerous places to visit? (hint: no)

There are several different ways to look at questions like this. One is to grant that there is an increased risk of injury, and then try to put that risk in the context of other things that raise our risks. Then we can see whether equally risky things are well thought of as dangerous or not. For example, people often say things like, "You think doing X is dangerous? It's safer than driving your car to the store." That's a fair point if it's true. On the other hand, as we saw last time, driving your car is extremely safe, at least with respect to the chance of being killed in an accident. If the store is less than 6 miles away your chance of being killed in an accident is less than 1 in 10,000,000. I don't think visiting Jerusalem for 6 days will be as safe as a trip to the store. So the question is, how safe is it?

There were 213 deaths in Israel from terrorist attacks in 2003. Many of these were outside Jerusalem. On the other hand, the year before there were about twice as many victims. So let's exaggerate the apparent risk by supposing 365 people will be killed by terrorists in Jerusalem in 2004, averaging one per day. The population of Jerusalem is over 6 million, plus there are always tons of tourists there. But let's use the figure of 6 million, again slightly exaggerating the real risk. So in a 6 day visit, that would make your risk 6 out of 6 million, which is 1 in a million. But remember, I've used numbers that substantially exaggerate the risk as far as we can tell. So, my risk of being a victim of a terrorist bombing during 6 days in Jerusalem seems to be well below 1 in a million. This is not as safe as driving to the store. And driving to the store is not as safe as huddling under the bed. But some things are more fun than others too.

[Note July 7, 2004: In the above paragraph I meant to state the population of Israel, not Jerusalem, resulting in a risk assessment for a trip to Israel, not specifically a trip to Jerusalem. The reason for this is that I could not find figures for bombings specifically in Jerusalem.]

That settles that, I think: a visit to Jerusalem is not very dangerous. Well, wait. What counts as dangerous? Let's find some other 1 in a million risks of death and see if we think of them as dangerous.


OK, I found some. On this website about calculating risks, we find these on a list of 1 in a million risks of, apparently, death. The first two are apparently risks of death from cancer, and the others are explained:

- smoking two cigarettes
- drinking 30 diet sodas with saccharin
- eating one hundred fifty (1/2 lb) charcoal broiled steaks (aromatic hydrocarbon risk)
- eating four tablespoons of peanut butter every 10 days for person without hepatitis B1
- drinking seventy pints of beer per year (alcohol cancer risk)
- one quarter of a typical chest X-ray
- traveling 100 miles in a motor vehicle
- dying from a lightning strike in a 6 year period

The beer one is not clear. I'm guessing it means that seventy pints of beer per year gives you a one in a million lifetime risk of dying of alcohol cancer, but it's not clear. I do know that I'll think twice the next time I'm tempted to eat 150 charcoal broiled steaks.

Really, this is not a very informative list. It doesn't let us compare the safety of beer and diet soda, because it is only listing one of the risks that each one poses. Alcohol comes with health risks other than alcohol cancer, along with some benefits. But a few of these do seem to give us useful comparisons to the risk of spending 6 days in Jerusalem. The terrorist risk is about the same as the fatal cancer risk from two cigarettes. And about the same as the risk of dying in a 100 mile car trip.

Again, notice how tricky this is. I might very well take a 100 mile car trip when I'm in Jerusalem. I did the last time I was there. Now what? This doubles my risk of death. That sounds bad. Well, it's not bad. It puts the risk of dying at the same level as the risk of a fatal crash on a 200 mile car trip in the U.S. And we have seen that this is an extreeeeemely small risk.

I'll be fine. But just to be safe, while I'm away, I'll lay off the steak.

Wednesday, April 07, 2004

Fear Itself 

I'm scheduled to travel to Jerusalem in early June. Nah, I'm not worried. Well, not about being harmed. I am a little worried about being a victim of terrorism though. The vast majority of victims are not harmed. That's the point of terrorism: they're terrorized. Ever since the Sept. 11 attacks I've been telling anyone who'll listen how important it is for people to educate themselves about the risks, in order to appreciate how tiny they are. They're tiny. I'll come back to that.

But I admit I do understand the fear of fear itself. We all fear some things that we know are either not dangerous at all or very, very unlikely to hurt us. Most phobias are like that, but we all experience it in milder forms. I was once building a tree fort a little too high up (never finished it...too high up). The extension ladder was secured to a branch. And climbing the higher rungs on the ladder is very much like climbing the lower ones, pretty easy really. But taking the last three steps to get up onto the tree was almost impossible for me. Also, by the way, for everyone else who tried it, which included about six people who wanted to come up and see how it was going. No one but me and the neighbor guy who was helping me ever took that last few steps. They couldn't do it. They were too afraid, even though they knew the next step was just like the first one, and nothing was going to happen. So you don't avoid the next step to avoid getting hurt. You avoid it to avoid being afraid, even though you know you're not going to be hurt.

The fear of being harmed by terrorists is like that. Imagine that your are flying into Tel Aviv (wait, that's me). Even though you know (or you will soon, when I get to that part) that there is (almost) no way you're going to be hurt, you might get scared anyway. And then it makes a certain amount of sense to change your plans if it's not worth it to be that afraid. So, maybe it's been unfair of me to chastise the public for changing their travel plans and harming the economy, causing unemployment, instilling even greater fear at the power the terrorists seem to have to harm the economy, etc. Hmm, nope, I don't think it was unfair. The reason is that the fear is a lot less bad if you get your mind around the probabilities of you or someone very close to you actually being hurt by a terrorist. And add to that the fact that the terrorists' biggest weapon is exaggerated fear. Conclusion: think about the risks and don't give in to irrational fears. That'll show em.

Now, probability suggests something precise, but there is no precise probability of anyone's being hurt by a terrorist. So, some people say, this whole probability thing is no way to show people are too scared. But the problem is that much of the fear is itself the result of some beliefs about the probability of being hurt. So, if probabilities are simply not available in this area at all, that would be enough to show that much of the fear is all confused and irrational. But, actually, probability applies. Not in any precise way, but well enough to help undermine some of our frightening beliefs. There's this kind of analogy: are you more or less likely to be harmed by a terrorist on a flight to Israel than you are to be struck dead by lighting playing 36 holes of golf? The answer is much, much less: they get you AFTER the flight, in the airport, in Tel Aviv.

Wait, that's not my point. Let's throw in the flight and the passage through the airport. To be fair, then, we'll include a beer at the clubhouse along with the golf game. No, we can't really do that. No data. The truth is, there's not enough data anyway. There is tons of data on the risk of being struck by lightning playing golf. But terrorist downings of planes going into or out of Israel are virtually nonexistent. That doesn't mean there's no risk. The risk is probably higher now than at many other times. But there are no good numbers to play with, because it just hasn't happened.

We can say this much: suppose you think one plane into or out of Israel will be attacked in the next year. The truth is, of course, that this is not at all certain to happen. But suppose it were. How much risk are you at if you take a trip to Israel? Well, there seem to be about 10 million passengers passing through Tel Aviv's Ben Gurion Airport in a year (as of 2000). If a plane goes down, let's suppose it has about 100 people on board. Each of the 10 million passengers has a 1 in 100,000 chance of being on that plane. This is about the same as the chance of being killed on a 600 mile drive. There is about 1 death for 60,000,000 miles driven, which equals .00001 deaths for 600 miles driven, or 1/100,000.

How does this help? I find it helps in two ways. To be honest, driving on long trips makes me nervous. Vaguely, in the back of my mind, I fear that there's a significant chance of a fatal accident. (Actually that fear is right at the front of my mind after a six-pack. Just kidding.) It has to help to find out that the chance is really very low. A 600 mile trip is about a 10 hour trip, and it is a very pleasant surprise to know that chances of a fatal accident are only about 1 in 100,000.

The second way it helps is that, even before I learned how low the risk really is, the risk in driving never stopped me from taking long car trips. (I drive about 900 miles to Nova Scotia every summer with my family.) This seems to be true for most people. A ten hour drive is hard work, but very few people chicken out or plead with loved ones not to take the chance. Even if I think terrorists will down a plane into or out of Israel this year, flying there doesn't put me in any more danger of being one of the victims than the risk of dying in a 10 hour car trip. It is the kind of risk we do, and should, take in stride. Especially, when it is someone's nefarious goal to make us exaggerate the risk and change our behavior. More on that soon.

And you might be wondering about the risk of dying in a suicide bombing during a 5 day stay in Jerusalem. I'll get to that.

What? Me worry?

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