In a number of studies we examined the criminal trajectories of two subsamples of our longitudinal “Toronto” sample. Together, the Toronto sample comprises the entire population of 764 male offenders who had served a sentence between January 1, 1986 and December 30, 1997 at one of two open custody facilities (i.e., group homes), operated by a children’s mental health centre in Toronto, Ontario.
For each study, we conducted two sets of statistical analyses. First, we performed trajectory analysis to derive a small number of clusters of individuals who follow statistically similar criminal trajectories across the follow-up period. Second, we applied multinomial regression analysis to identify the childhood and adolescent risk factors associated with trajectory group membership. A particular aim of these studies was to isolate the factors associated with the high rate and chronic offender groups.
Sample A: Initial follow-up.
In the first study, a randomly selected sample of 378 youth, referred to as “Sample A,” was identified for investigation. This sample was, on average, 17.6 years at the time of admission into the facility and the average sentence length was 124.6 days. Their criminal activity was tracked for an average of 12.1 years (range = 5.8 – 22.8 years), from their first recorded court contact to March 17, 2001. The average age of their first court contact was 15.5 years.
Sample A: Extended follow-up.
For the second study, the length of the follow-up period was extended to 18.7 years, on average (range = 12.3 – 29.3 years), to September 26, 2007. The average age at the end of the 2007 follow-up was 34.1 years. About 88% of the sample was followed for 16 years or more.
Sample B: Follow-up.
The remaining 386 offenders constituted the second subsample, referred to as “Sample B.” This group was, on average, 17.7 years at the time of admission into the facility and the average sentence length was 122.6 days. Their criminal activity was tracked for an average of 16.4 years (range = 9.8 – 28.7 years), from their first recorded court contact to September 26, 2007. Their average age at first court contact was 15.6 years and the average age at the end of the follow-up period was 32.0 years.
A strength of these studies is that the follow-up periods extended from late childhood (for offences committed under the Juvenile Delinquents Act [JDA]) and early adolescence into adulthood. This time span represents a substantial period for which to investigate criminal offence trajectories from a life course perspective. A research report on this work may be accessed from the National Crime Prevention Centre (NCPC website at http://publications.gc.ca/collections/collection_2012/sp-ps/PS18-4-2011-eng.pdf (English version) and http://publications.gc.ca/collections/collection_2012/sp-ps/PS18-4-2011-fra.pdf (French version).
Photo credit: Surian Soosey, https://www.flickr.com/photos/ssoosay/