Three pathways were hypothesized in the authors' previous work: an Authority Conflict Pathway prior to the age of 12, which starts with stubborn behavior and has defiance as a second stage and authority avoidance as a third stage; a Covert Pathway, which starts with minor covert acts, has property damage as a second stage, and moderate to serious delinquency as a third stage; and an Overt Pathway, which starts with minor aggression, has physical fighting as a second stage, and violence as a third stage. The previous work is refined in the current study by distinguishing between boys who experiment with delinquent behavior and those who persist in disruptive behavior. Boys attending the first, fourth, and seventh grades in the Pittsburgh Public School system were randomly selected for participation in a longitudinal study of the development of disruptive and delinquent behaviors. Only boys from the oldest (n=506) and middle (n=508) cohorts were included in this study due to the low base rates of more serious problem behaviors in the youngest cohort. Using both self-report and court adjudicated offenses, the data show that the fit for the three pathways is better for persisters than for experimenters. Also, the proportion of persisters that enter each pathway at the first stage (rather than at later stages) is higher than that for experimenters. Penetration in each pathway was more common among boys who received a diagnosis of Attention-Deficit Hyperactive Disorder. Boys' rate of offending increased with penetration into pathways and with persistence on more than one pathway. Boys' persistence and advancement in the Overt or the Covert Pathway was invariably accompanied by their advancement in the Authority Conflict Pathway. The classification of boys according to persistence and pathways accounted for the majority of high-rate offenders. The authors discuss the implications of the findings for assessment and intervention. 4 tables, 5 figures, and 34 references