Aim: The main aim of this article is to compare prevalence and frequency, ages of onset and desistance, and criminal career duration, according to self-reports and convictions.
Method: In the Cambridge Study in Delinquent Development, 411 London males have been followed up from age 8 to age 48, in interviews and criminal records.
Results: Virtually all males admitted at least one of 8 offences, compared with about one third who were convicted. In self-reports, the number of offences was over 30× greater, the age of onset was earlier and the career duration was longer, compared with convictions. However, the age of desistance was generally later according to convictions.
Conclusions: Self-reported ages of desistance may be affected by increasing concealment with age. The gap between the first self-reported offence and the first conviction provides an opportunity for early intervention.
…The age of onset has been studied in self-reports compared with official records. LeBlanc & 1989 in Montreal found that the average age of onset was 10.8 in self-reports and 14.6 in official records (up to the early twenties). et al 2003 in Pittsburgh reported average onset ages of 11.9 and 14.5, respectively, whilst et al 2003 in Seattle reported corresponding ages of 12.7 and 15.1. In the CSDD up to age 32, 2005 discovered that, for males with both self-reports and convictions, average self-report onset ages ranged 10.7–15.2, whilst average conviction onset ages for the same offences ranged 16.8–22.7.
…During the interviews at ages 14, 16, 18, 21, 32 and 48, the CSDD males were asked to self-report offences that they had committed that had not necessarily come to the notice of the police…These results are greatly affected by the rather atypical offences of theft from work and fraud. Focusing only on the other 6 offences, 95.8% of males admitted at least one of them, and the average offender committed 30 offences. The average criminal career of 9.6 years began at age 9.9 and finished at age 19.5. According to self-reports, most males began between ages 8 and 12 and finished between ages 14 and 21.
…It was expected that the prevalence and frequency of offending would be higher according to self-reports than according to convictions, and this was indeed found. Over 8 offences, there were 112 self-reported offences per offender on average, compared with 3.3 convictions, a ratio of 34:1. Between 1% and 28% of different types of offences led to convictions.