The model was applied to test the predictions of trajectory theories that offending history data can be classified into early onset/life-course-persistent offending and late onset/adolescent-limited offending trajectories, with these trajectory groups being related to different etiological factors. The approach was applied to data gathered over the course of a longitudinal study of more than 900 New Zealand children studied from birth until the age of 18. Analysis identified four trajectory groups corresponding to non-offenders, moderate risk offenders, adolescent onset offenders and chronic offenders. Social, family, childhood and peer factors associated with these offending trajectories suggested the presence of a series of common etiological factors relating to family functioning and early adjustment that discriminated between the trajectory groups. However, evidence of trajectory-specific etiology also existed, in which formation of deviant peer affiliations for young people from moderate risk backgrounds led to the rapid onset of offending in adolescence. Notes, tables, references