California’s Attorney General was pleased to announce that “An unintended but positive consequence of ‘Three-Strikes’ has been the impact on parolees leaving the state….The growth in the number of parolees leaving California is staggering.” Law enforcement officers in other states were presumably less pleased. A displaced criminal is a benefit to California but a cost to other states. If such criminal spillovers are important, law enforcement will over-invest in policies that encourage displacement. We test whether California’s three-strikes law led to significant criminal spillovers.
That's the abstract from my latest paper, Measuring Criminal Spillovers: Evidence from Three Strikes (with Eric Helland). In an earlier paper, Helland and found–by comparing statistical doppelgangers some subject to the law some not–that three strikes does deter (whether it deters eneough to be good public policy in less clear). In this paper, however, we found that three strikes does not cause appreciable exit of criminals from California (or appreciable reduction in entry), i.e deterrence does not occur on the relocation margin. During the time that California's AG spoke, everyone was leaving CA not just criminals. One conclusion of our research is that a federalist approach to crime remains viable.