How many latent classes of delinquent/criminal careers ? Results from mixed Poisson regression analyses

This article reviews questions about different categories of criminal careers, summarizes Poisson latent class regression models, describes procedures for evaluating the optimal number of latent classes, and applies this methodology to data from male cohorts taken from the cities of London, Philadelphia, and Racine. Four latent classes of offending careers is an appropriate number for the London cohort, but five classes can be justified for the Philadelphia data.