This is a collaborative study on criminal careers (with Land, SES92-10437). The study will test two competing models of criminal careers. One model suggests that there are two classes of offenders (frequents and occasional) and that each has a different probability that an offender desists criminal activity after a certain number of convictions. The second models assumes that each individual in a population has a propensity for engaging in criminal behavior, and that the offending rate for an individual remains constant over the life course. The study will employ mixture Poisson regression models and latent-threshold normal regression models to analyze data from three longitudinal data sets on criminal activity. This study will increase our understanding of patterns of crime over individuals' lifetime and of the social and individual characteristics associated with criminal careers.