[Eugene Volokh, November 14, 2007 at 7:34pm] Trackbacks
"A CBS News Investigation Uncovers A Suicide Rate for Veterans Twice That of Other Americans" -- Or Does It?
The quote is drawn from this CBS News story, with results that CBS labels "stunning." And the story claims that the stunning results indeed remain robust when one controls for sex. Here's the data on the Methodolgy page:
Results for 2004
Overall Rates
Veterans: 17.5 to 21.8 per 100,000
Non-Veterans: 9.4 per 100,000
Male Rates
Veterans: 30.6 to 38.3 per 100,000
Non-Veterans: 18.3 per 100,000
Female Rates
Veterans: 10.0 to 12.5 per 100,000
Non-Veterans: 4.8 per 100,000
Results for 2005
Overall Rates
Veterans: 18.7 to 20.8 per 100,000
Non-Veterans: 8.9 per 100,000
Male Rates
Veterans: 31.5 to 35.3 per 100,000
Non-Veterans: 17.6 per 100,000
Female Rates
Veterans: 11.1 to 12.3 per 100,000
Non-Veterans: 4.5 per 100,000
Yet here's something odd about the data: For the overall rates to correspond to the male and female rates, the veteran pool would have to be 62% to 64% female, and the nonveteran pool would have to be about 66% female. Check it out, for instance, with the lower bounds on the 2005 data: 11.1 x 0.63 (female) + 31.5 x 0.37 (male) = a bit under 18.7 (overall).
Or, if you prefer, consider a veteran pool of 23 million people. You'd need:
* 14.5 million (23 million x 0.63) women, or 145 hundred-thousands, with 1610 suicides (145 x 11.1) and
* 8.5 million (23 million x .037) men, or 85 hundred-thousands, with 2680 suicides (85 x 31.5) to get
* a total of 4290 suicides (a bit under 18.7 per 100,000) for the whole 23 million.
That can't be right. The VA reports that the veteran pool is only 7% female, which means that if the CBS News overall veteran and female veteran numbers are right, then the male veteran numbers would be 19.27 to 21.4 in 2005 and 18.06 to 22.5 in 2004, not far from the male suicide rate of about 17.7 per year (see WISQARS). Of course, we can't tell which of the CBS numbers are right — but it does seem like they can't all be right. Plus of course you can't have a population that's about 51% female but at the same time 62-64% female among veterans and 66% female among nonveterans.
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