Statistics As They Float By

Because I have been in doctors' offices recently, I have read many more magazines than I usually do. Wouldn't you think, BTW, that eye centers would have a few large-print magazines in their waiting rooms? Mine don't - not in three different offices.

I was reading the Sports Illustrated article about the college pitcher who was just coming to the end of his successful five-year probation for sexual abuse of his niece when he was in highschool, when the whole story came to light and now major league teams don't want to draft him because of the bad PR, and risk of worse problems down the road.

The case is interesting, because he pled guilty and likely is guilty, but also claims he only pled because he was assured it was the best way to keep everything quite and make it go away as quickly as possible. That last is true, and people do that all the time, so it raises questions.  I haven't got enough data to comment further on that, and that's not the point of the post anyway.

There was an outraged college administrator who was appalled that the university had let his arrival and playing for one of their teams happen.  In her quoted statement, she said that 75% of female drug and alcohol addicts had been sexually abused, and that 75% of women having gastric bypass surgery had been sexually abused. I have a little more than average experience with women who have had gastric bypass surgery than the average person, because they are overrepresented among psychiatric patients, but I don't know an enormous amount about it.  I know that obesity is much more common among sexually abused females* (and probably males). Yet I knew even as I was reading the sentence I knew that 75% was very likely to be too high. I was immediately irritated because if she is going to be paid a handsome salary to advocate on these sorts of matters, she has a responsibility to get these things right.  It's her job.

To me the interesting piece is how I instantly knew it was bogus.  First I will give a retrospective, but I warn you that I will go on to undermine my own reasoning, so don't get swept away.

There were two 75%'s back-to-back. Red flag. Just too convenient. Son #5 uses the phrase "Shit just comes out of her mouth." Next, the first statistic isn't really about the topic at hand.  Adult substance abusers are indeed victimised at a very high rate. That's not the same thing, but she talks as if it its. It doesn't say that 75% of women who were sexually abused as children will become substance abusers as adults, nor that 75% of adult substance abusers were sexually abused as children. Those would be relevant.  Her statistic is is shouting distance of the subject at hand, but no closer. I saw that because I did an immediate reread, because some of this is my profession and I reflexively double-check. Third, 75% of any two small, seemingly unrelated groups is a lot of people.  If someone says "75% of Mennonites..." (or mixed-race Canadians, or county employees, or members of the garden club) "...play a wind instrument" alarm bells should go off.  It's just too weird. BTW, the real number is 25-30% - a big number, but not crazy big.

So far, most people would agree with my reasoning, and noticing their own sizing up of situations on the fly, don't find this all that surprising.  Somehow we all have these amazing shortcuts, part of  Daniel Kahneman's Thinking, Fast and Slow.

Except sometimes these shortcuts are wrong, yet we are just as sure about them. This is where the post got away from me. Researching this, I came quickly back to Kahneman, and this short interview. But that of course (well, to me, anyway) led to CS Lewis's Meditation In a Toolshed. (PDF) It is excerpted and commented on here. I went back to browse in my own 2011 series May We Believe Our Thoughts, but I don't like reading that much of my own stuff. Hopefully I wrote smart things.  If any of you do browse, let me know.

*The two simplest theories are that the abuse creates a need to be unattractive, or that the emotional pain creates a need to self-soothe with food. I think those are true but more complicated things are true as well. Perpetrators have an ability to identify those who are less-capable of standing up to them and turning them in. In many cases both mother and daughter (there is the genetic-environment conundrum again) are willingly blind or too fearful to speak.