The Bridge Factor

In the course of questioning the utility of suicide-proof barriers on bridges, a political scientist makes an intriguing observation:

In order to determine if exposure to bridges increases the suicide rate, I examined the relationship between the suicide rate and the number of bridges likely to attract suicidal individuals in all 50 states plus Washington D.C. from 1979 through 2004 (the only years for which complete data was available). Bridges likely to attract suicide victims were defined...