The study found that starting drug use increased the risk of the user escalating to regular offending. Cannabis had a direct, independent effect on increasing the risk of offending escalation. The use of other illicit drugs increased the risk of offending escalation over and above the risk attributable to cannabis alone. If an offender started using drugs but did not escalate to regular offending in that same year, the risk of an offending escalation decreased with each subsequent year that escalation did not occur. Young and/or Indigenous offenders were more likely to escalate to regular offending within the first 10 years of their criminal career. This finding was not related to the offender's drug use. Based on these findings, the study concludes that preventing drug use will reduce the probability that an intermittent offender will escalate to regular offending. Delaying drug use should also reduce the number of lifetime offenses. Prevention policies should target younger offenders and those who begin using drugs subsequent to or at the same time as their first offense, since this is the time period in which drug use exerts the greatest influence on offending frequency. DUCO was an interviewer-administered, self-reported survey of offending and drug use conducted in 2001 among adult male prisoners in Queensland, Western Australia, Tasmania, and the Northern Territory. Using a survival analysis technique, the study examined the risk profile of 1,500 property offenders and their likelihood of escalating from intermittent offending to regular offending. The time when drug use started was examined in relation to any changes in offending patterns. 11 tables, 15 figures, and a 93-item bibliography