In the news lately, there've been a few particularly egregious examples of bad math. One that really ticked me off came from Alan Simpson. Simpson is one of the two co-chairs of a presidential comission that was asked to come up with a proposal for how to handle the federal budget deficit.
The proposal that his comission claimed that social security was one of the big problems in the budget. It really isn't - it requires extremely creative accounting combined with several blatant lies to make it into part of the budget problem. (At the moment, social security is operating in surplus: it recieves more money in taxes each year than it pays out.)
Simpson has claimed that social security must be cut if we're going to fix the budget deficit. As part of his attempt to defend his proposed cuts, he said the following about social security:
It was never intended as a retirement program. It was set up in ‘37 and ‘38 to take care of people who were in distress -- ditch diggers, wage earners -- it was to give them 43 percent of the replacement rate of their wages. The life expectancy was 63. That’s why they set retirement age at 65
When I first heard that he'd said that, my immediate reaction was "that miserable fucking liar". Because there are only two possible interpretations of that statement. Either the guy is a malicious liar, or he's cosmically stupid and ill-informed. I was willing to accept that he's a moron, but given that he spent a couple of years on the deficit commission, I couldn't believe that he didn't understand anything about how social security works.
I was wrong.
In an interview after that astonishing quote, a reported pointed out that the overall life expectancy was 63 - but that the life expectancy for people who lived to be 65 actually had a life expectancy of 79 years. You see, the life expectancy figures are pushed down by people who die young. Especially when you realize that social security start at a time when the people collecting it grew up without antibiotics, there were a whole lot of people who died very young - which bias the age downwards. Simpson's
response to this?
If you’re telling me that a guy who got to be 65 in 1940 -- that all of them lived to be 77 -- that is just not correct. Just because a guy gets to be 65, he’s gonna live to be 77? Hell, that’s my genre. That’s not true.
So yeah.. He's really stupid. Usually, when it comes to politicians, my bias is to assume malice before ignorance. They spend so much of their time repeating lies - lying is pretty much their entire job. But Simpson is an extremely proud, arrogant man. If he had any clue of how unbelievably stupid he sounded, he wouldn't have said that. He'd have made up some other lie that made him look less stupid. He's got too much ego to deliberately look like a credulous drooling cretin.
So my conclusion is: He really doesn't understand that if the overall average life expectancy for a set of people is 63, that the life expectancy of the subset people who live to be 63 going to be significantly higher than 63.
Just to hammer in how stupid it is, let's look at a trivial example. Let's look at a group of five people, with an average life expectancy of 62 years.
One died when he was 12. What's the average age at death of the rest of them to make the overall average life expectancy was 62 years?
So in this particular group of people with a life expectancy of 62 years, the pool of people who live to be 20 has a life expectancy of 74 years.
It doesn't take much math at all to see how much of a moron Simpson is. It should be completely obvious: some people die young, and the fact that they die young affects the average.
Another way of saying it, which makes it pretty obvious how stupid Simpson is: if you live to be 65, you can be pretty sure that you'll live to be at least 65, and you've got a darn good chance of living to be 66.
It's incredibly depressing to realize that the report co-signed by this ignorant, moronic jackass is widely accepted by politicians and influential journalists as a credible, honest, informed analysis of the deficit problem and how to solve it. The people who wrote the report are incapable of comprehending the kind of simple arithmetic that's needed to see how stupid Simpson's statement was.