This report describes an information theoretic approach for estimating the number of crimes averted by incapacitation. It develops models of the criminal history accumulation process of a sample of individuals released from prison and uses the models to compute the number of crimes these individuals could reasonably have been expected to commit had they not been incarcerated. The models also afford the opportunity to conduct a limited set of policy simulations. Although a fair amount of heterogeneity is found among individuals, estimates do not vary sufficiently by gender, race or ethnicity. Variations across states and offense types are more pronounced.