Estimating the numbers of arrests as a function of an offender's age

Criminology Research Council grant ; (22/94-5)

This research developed new methodologies for displaying and analysing arrest profiles and criminal career projections. Applied in relation to comprehensive longitudinal data bases, the research concluded that these methodologies permit fundamental criminological questions such as the impact of age-at-onset upon subsequent criminal careers to be re-visited. Though the methodology as described in the report is applicable to all-aged criminal careers, its application in this study focused on criminal careers commencing as juveniles. It studies the arrest profiles of all persons who commenced a criminal career, either as juveniles or later in life, in Western Australia between 1 January 1984 and 31 December 1994.

The research concluded that age-at-onset is indeed associated with both the frequency and intensity of subsequent criminal careers. The analysis also revealed the dominance of Aboriginality, particularly male Aboriginality. For example, the data shows that male Aboriginal people entering the arrest population on average commence their criminal career at a younger age, accelerate them more rapidly, and accumulate them to a markedly greater extent than any other race/sex subdivisions. However, the research conclusions emphasises that the methodology is equally applicable to any categories that constitute comparable focal groups in any jurisdiction. Moreover, this methodological approach would enable far more reliable projections to be made as to the cross-over rates from juvenile to adult criminal career.