Lots of abortions happened. Violent crime rates went down 15 to 20 years later.
The problem with this analysis is that a whole lot of other things also happened. Isolating the effects of abortion as compared to the other huge changes in our society during this period seems to me to be an insurmountable challenge.
I agree. The best method for analyzing and determining the drop in violent crime rates would be to look specifically at the economy, as well as the various types of violent crimes, and their numbers relative to each other. Changes in social mores, educational institutions in those areas, and immigration/migration patterns also play a role.
I for one think that a correlation between abortion and a drop in violent crimes may exist, but that doesn't mean that the correlation is the same as a direct cause and effect relationship. It is merely and interesting factoid without any real substance.
Of course, if we can borrow Karl Rove's "Alternate Universe Multi-Dimensional Television" set, we may be able to put the question to rest. In that case, we'd be able to identify babies aborted in this time line who weren't in other timelines, and develop statistics on how many of them became violent criminals... But Rove isn't likely to lend us his AUMD any time soon... Perhaps after the 2008 elections...