I was thumbing through one of this months magazines (I think Family Circle) and came across one of the stories designed to scare people. This one was about how dangerous it is to be a pedestrian. Alone with tragic mini accounts of people who were hit by cars there was this statistic " In the US 6000 pedestrians a year are killed by motorists, and another 9,000 a year are injured." Sure, ok, that could be true. However, in their little fact box it stated that " You are 35 times more likely to be killed while walking than driving." Wait a second, how could both of their facts be true? Wouldn’t that mean that less than 175 people a year were killed while driving? Even if you rule out passengers killed in car accidents, I’d say 175 people would be a fraction of the** drivers** killed in a single day across the country. Or if we assume that they came up with the figure “35x more likely” by more specifically comparing only those who walk frequently to those who drive more frequently, the precentage of people who walk can’t be that small compared to those who drive, can it? College students living on “walking campuses” alone have to account for millions of pedestrians.
This seems like a weekly occurance on the local news too, there’s always a feature story about-something-you-had-no-idea-was-dangerous-possibily-killing-you. Most of these stories take something minor and blow the danger of it out of proportion…but why? I suppose it’s partly due to ratings, but take where I live for example, there’s only one station that plays relatively local news, so were I to watch the news that night, I’d naturally tune into that station. The station must realize that it has a more or less captive audience, but it does the same sort of stories…Is it just sadism?
One explanation could be that the comparisons are not equivalent. The first stat applies to number killed in total; the second stat could be numbers killed per hour engaged in the activity, or per mile covered.
It’s not sadism, just stupidity, and a complete lack of understanding about math.
You have to understand that the people who write news (be it magazines, tv, radio or newspapers) are, by and large, incapable of balancing their chequebook.
(Not me! I passed Calculus I, but it’s been a looong time since I tried to integrate an equation.)
Did the magazine provide a cite? No? Then they may :eek: have pulled the figure out of thin air, or a dubiously researched piece by another journalist who doesn’t understand statistics.
When you see/hear stuff like this on local TV and radio, chances are it came from a wire agency like Reuters or CNN, and it seems like the people who write for them can barely spell, let alone do sums.
I don’t know how many times I’ve thrown a script back at someone and said something like “No, the price going up 5 cents does not mean a 5 percent increase!” Unfortunately, people like me are rare
Memorize the following three statistics: These don’t change that much each year, so there’s a pretty good chance that these numbers will stay constant for the forseeable future. First, the number of people who die in auto accidents in the U.S. each year is about 40,000. (So, in fact, the number of people killed per day is a bit more than 100, not much greater than 175 as you guessed, elfkin477.) This number is very slowly dropping, but at a rate that it will take a decade or so to drop by a thousand. There’s two things going on here. Cars, roads, and driving habits are slowly and steadily getting safer, but people are driving more each year. Second, the number of people who commit suicide each year in the U.S. is about 30,000, and this number changes very little from one year to the next. Third, the number of people murdered each year in the U.S. varies between a little more than 25,000 when the crime rate in general is high to somewhat less than 20,000 in a year when the crime rate is low (as is presently the case).
I think it’s useful to know these numbers because it’s amazing how many people worry about whether they will be murdered and what they can do about it, while they don’t ever think about the possibility that they will commit suicide or die in an auto accident, although those are more common sorts of death. This isn’t because a murder is more preventable than a suicide or an auto accident. There are lots of things you can do to reduce your risk of dying in an auto accident. You can not drive while drunk (or even near-drunk), you can wear your seatbelt, you can not speed, etc. There are things you can do to reduce your chances of committing suicide, like getting help if you suffer from depression. I suppose there are a few things that could decrease somewhat your chances of being murdered. You could get out of an abusive relationship before it gets bad and you could stay out of dark alleys, I suppose. Some of the things that you think might prevent your being murdered, like getting a gun to protect yourself, are at least dubious and probably counterproductive. What few things there are that will really change the number of people killed each year are general societal things that aren’t well understood.
One more statistic you should memorize. The number of people killed by lightning in the U.S. each year is about 100. Being struck by lightning is sometimes portrayed as being an incredibly rare (and totally unpreventable) event, but it’s more common than some other things that gotten much bigger play in the media. (For instance, the number of abductions of a child by a stranger in the U.S. is less than 100 per year.) And there are things you can do to avoid being struck by lightning, like not running under a tree when you hear thunder.
I love this little gem. It fits your article so well.
I get a kick out of these types of articles(OP). In fact, I’ve been known to cut them out and share them with classes (when I taught) just to point out fallacies. This biggest fallacy is usually poor comparisons (the old “apples” and “oranges” thing) or funky denominator tricks.
One example of this is when a report comes out that you are twice as likely to die while walking than while driving - or some such. It does not consider that at any point in time more people are walking than driving, and other such factors. This, and similar misuses of statistics show poor design, poor understanding by the author and often banks on a poor understanding of the audience.
As an aside, three of the people (out of 30 or so - see? the denominator is important!) in my first graduate level statistics class were from the school of journalism. It was a required course for them. Good for the school of journalism.
WW thanks for that link. The point about the death rates (accident/suicide/murder) is dead on - that they change very little over time. Of course, the media uses these as major indicators! I guess my work is not yet done…
I think what the story in the OP meant was that if you get in a traffic accident that’s serious enough to cause injury, you’re 35 times more likely to get killed on foot than you would be in a car.
If 6000 people a year die as pedestrians in accidents while another 9000 are injured, as stated in the OP, that means that if you get hit by a car while you’re on foot, and it’s serious enough to cause injury, your chance of getting killed is 40 percent.
According to one source I found, in 1999 there were about 40,000 people killed and 3,200,000 injured in traffic accidents. (I’m not sure if the 3,200,000 figure includes fatalities or not.) That means that if you’re in an auto accident serious enough to cause injury, and you’re in a car when it happens, your chance of getting killed is 1.25 percent.
Forty percent is 32 times 1.25 percent, which is close enough to 35. Whoever wrote and/or edited the magazine article should have made this clear.
Wendell Wagner, that is very well put and very reasonable. Unfortunately people tend to be less reasonable so, rather than change their own behavior they tend to think what others can and should do. That is why people who do all sorts of dangerous and unhealthy things on a daily basis are so ready to sue someone else for something much less dangerous or unhealthy.
I started a thread about a year ago regarding the use of statistics to prove anything but it did not raise much interest. (I think it was because I used an example with actual numbers)
I don’t think this is the case in the article referenced by the OP, but we must remember that there are also people who will simply lie to journalists about statistics, and hope that the journalist lacks the time, ability, or inclination to check the data or the math.
Patricia Pulling was particularly notorious for this kind of behavior, and her “Satanic conspiracy” statistics were widely quoted at one time. Michael Stackpole’s Pulling Report quotes a number of examples of the kind of statistical lies an unscrupulous individual with an axe to grind can often get published as fact.
This quotation is usually attributed to Benjamin Disraeli. I’ve read/heard that Mark Twain actuall said a very small fraction of the things attributed to him.
In fact, according to the link I posted above, Twain attributed that quote to Disraeli. I think the confusion stems from the fact that it’s such a Twainish phrase, combined with Twain’s quoting of it.
Quite a few people I’ve met tend to associate any folksy (possibly profane), cynical quote they hear with Twain, if they aren’t sure of the source. (I prefer to guess “Ambrose Bierce”, if only so that I can direct people to the “Devil’s Dictionary”.)
