Didn't that same assertion come out in the first Freakonomics book? The point being that Guiliani's focus on squeegee men and broken windows didn't have as big an effect on crime as the Roe v Wade decision and the abortion of millions of potential criminals?
I wonder if they also pondered that with a population of (57 million) and asked how many inventors, doctors, theologians, soldiers, scientists etc., and how many of their children could have been alive in the world,
When you kill someone, you also kill everyone that would have ever come from them,