Empirical economic analyses of deterrence attempt to test the central prediction of Becker's (1968) rational-actor model of criminal behaviour: that less crime occurs when the expected penalties are greater. When economists have broken the simultaneity of crime rates and crime-control policies, they have generally concluded that policing levels and the scale of incarceration reduce crime rates. Economists have made less progress in determining whether these reductions in crime are due to deterrence or incapacitation, but the research suggests that both effects are likely present. Evidence on the deterrent effect of capital punishment and particular victim precautions is far less convincing.