Thursday, January 07, 2010

The Problem With Statistics--Crime Waves and Falls [Revised]

Mathew Blake at Understanding Government links to a Wall Street Journal piece on the fall of crime rates. The piece quotes some experts who say that the graying of the boomer generation is partly responsible, since people over 50 are unlikely to commit violent crime (as opposed to financial crimes, perhaps?) and that age group  is the most rapidly growing.  Mathew has some doubts, but I have a different question. Suppose we went back to the high crime days of the 70's and 80's and normalized the statistics for the age distribution--what would the statistics look like?  I'm sure it would reduce the amplitude of the the peaks, but by how much?  And if public discussion and the media had used those statitstics rather than the gross figures they did use, would California today be spending more on public schools and less on criminal schools (i.e., prisons). That's a factoid which caught my attention today--Schwartzenegger wants to decrease the money spent on prisons because they do spend more on prisons than schools.

[Revision: thinking more about this issue, it strikes me the statistical adjustment would need to be tricky, not just for the number of young in the population, but probably also for the percentage of young.  Seems to me the boomers in the 70's gained confidence from being such a large generation, while those of us in the "silent" generation realized we were outnumbered. I suspect everyone has experienced the intimidation factor of a group of young, rowdy males on a public street where there's only a handful of adults around.  Conversely, a large crowd of middle-aged and old people can establish a standard of behavior that cows a handful of teens/twenties.  So the question would be, in this hypothesis, how often each scenario occurred. ]

No comments: