Let n denote the number of juvenile offenders in the cohort and represent the recorded time to reappearance for the i-th juvenile offender as yi . A number of variables thought to have an effect on time to reappearance, denoted as xil, … xip , are observed for each juvenile in the cohort ( i = 1,...,n ). Conditional on the set of covariates xil, … xip , times to reoffend, yi , are distributed according to :