[Pwnguinz]

Fair enough. There are plenty of studies out there regarding this topic, though a definitive conclusion is probably beyond any one single study. See papers Justin McCrary have published (he's done quite a bit of work in this area).

One such paper takes an interesting approach, combing the criminal records to see if the fact that deterrence is stiffened after 18 has an deterrent effect on crime rate by comparing juvenile offenders that are months pre-18 and 'adult' offenders that have just recently turned 18. The finding is 'surprisingly' a negative. Only very minor drop off rate is seen.

You can read the paper here: http://www.nber.org/papers/w11491.pdf