In 1992-93, 506 adjudicated boys were interviewed, representing virtually the entire population of boys who had been adjudicated under the Youth Protection Act or who had been found guilty of a criminal offense in 1992-93 and who had been placed on probation or in open or closed facilities. Of these boys, 288 (57 percent) were adjudicated for a criminal offense under the Young Offenders Act, and 218 (43 percent) were wards of the court for severe problem behaviors under the Youth Protection Act. The study used an analytical strategy that is a partial aggregate of developmental progression and dynamic classification strategies. Two developmental sequences were constructed: one for delinquency and one for problem behavior. Their combination generated various trajectories. The analysis focused on the difference between those boys with synchronous trajectories, in which problem behavior and delinquency followed similar developmental paths, and those with nonsynchronous trajectories, in which the two followed different developmental paths. Comparison of the trajectories showed that personal aggression and extroversion were more effective in discriminating between trajectories than were social control variables from school, peer, routine activities, and belief categories. These personal control variables are often not included in studies of delinquency. 3 tables and 66 references