Specialization and versatility in offending

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Criminological research on representative samples of offenders, rather than case histories of "professional" criminals, has consistently found little or no evidence of specialization in specific types of crime, but much evidence of specialization in broad categories of crime (Piquero et al. 2007: 75). However, specialization is more common in adult offenders than in children or adolescents (Ibid.). This section examines specialization and its obverse, versatility, in the delinquent careers of repeat offenders in the two birth cohorts. Offences are classified into three broad categories: offences against the person, offences against property, and other offences. Delinquent careers consisting of only one of these three categories are classified as specialized; those which include offences in two or three categories are classified as versatile. Thus, the criterion of specialization is quite broad.¹

Unlike the analyses in the other sections of this report, the analyses of specialization and versatility use information on up to four different violations of the law occurring in each incident.² Thus, it is possible for a career consisting of only one incident to be classified as versatile, if the offences allegedly committed in the course of the incident fall into two or more of the three broad categories of crime. In reality, this is rare: only 4.3% of single-incident careers were classified as versatile. This is probably because the majority of incidents recorded in the UCR2 have only one violation coded: of approximately 123,000 incidents included in this study, only 22,000, or 18%, have a second violation coded; only 6,000, or 5%, have a third violation, and only 1,800, or 1.5% have all four violation fields completed. Since single-incident "careers" characterize the majority of the study population (see the previous section), and 96% of them are specialized - almost by definition – their inclusion in the analyses would greatly skew the results. Therefore, the analyses are performed only on the careers of "repeat offenders": those with at least two incidents. The 18,753 repeat offenders constitute one-third (33.4%) of the offenders in the study.

The first two columns of Table 7 show the distribution of the careers of the repeat offenders in each cohort into specialized and versatile, and the sub-types of each category. The last four columns further sub-classify the careers according to the presence or absence of administrative offences. Thirty-five percent of repeat offenders born in 1987, and 43% of those born in 1990, had specialized delinquent careers. The percentage of specialists among repeat offenders born in 1987 (35%) is the same as that reported for court careers of 12 to 21 year olds born in 1979/80 (Carrington et al. 2005). Of the specialized offenders, 28% in the 1987 birth cohort and 15% in the 1990 cohort also had administrative offences in their careers. The proportions with administrative offences are much lower than Carrington et al. reported in their study of court careers (57%): the difference reflects the very low numbers of administrative offences committed by children under 12 years of age, and also pre-court screening processes which affect the composition of the study population in court-based research.

Only 7% (in the 1987 birth cohort) and 10% (in the 1990 cohort) of repeat offenders were specialized in offences against the person, and even fewer (4% and 2%) in "other" offences. The majority of specialized careers were in property offending (24% and 31% of repeat offenders). Careers specialized in property offences – with or without administrative offences – are the most common of the eight types of careers. Versatile careers in the 1987 birth cohort are split fairly evenly among three groups - property and person offences, property and other offences, and all three types of offences – with a much smaller number of careers including only person and "other" offences. In other words, versatile careers tend strongly to include property offences. The proportions are similar for repeat offenders born in 1990, except that careers consisting of property and person offences are much more common than the other types.

Figure 36 shows the relationship between specialization and the number of incidents in the career, for the repeat offenders in each birth cohort.³ The prevalence of specialization is inversely related to the number of incidents in the career. The curve for the 1987 birth cohort is much smoother, and shows that the decrease in the likelihood of specialization is especially pronounced as the number of incidents in the career increases from 2 to 5: the proportion of specialized careers drops from 50% to 20%. Over 90% of careers with 12 or more incidents are versatile. Figure 36 suggests the same conclusion that has been arrived at by most other research on the subject: that specialization and versatility in offending are largely explained by the volume of offending rather than by a tendency towards specialization or versatility on the part of the offender (Carrington et al. 2005: 30; Piquero et al. 2007: 79).

Since the age of the onset of offending has been found to be related to many other characteristics of the criminal career, it is of interest to know whether early-onset offenders are more or less likely to be specialized or versatile in their delinquent careers. Previous research on adolescent and adult offenders suggests a positive relationship between the age of onset and the likelihood of specialization: as the age of onset increases, the number of incidents in the career decreases, and therefore the likelihood of specialization increases (Carrington et al. 2005: 31; Piquero et al. 2007: 71-72). In other words, early-onset offenders are more likely to be versatile.

Figure 37 shows the relationship between the age of onset and specialization, for repeat offenders in each birth cohort.⁴ The expectation is confirmed only for offenders whose first recorded offence occurred at the age of 11 or older (for the 1990 cohort) or 13 or older (for the 1987 cohort). For offenders whose first recorded offence took place during childhood, specialization decreases with increasing age of onset: that is, early-onset offenders are more likely to be specialized. For offenders born in 1990, this could be due to the anomalous increase in total delinquent activity with increasing age of onset (see Figure 32), but that explanation does not apply to offenders born in 1987, for whom both the mean number of incidents in the career (Figure 32) and the prevalence of specialization (Figure 37) decrease with age of onset from 10 to 13 years. In view of the small numbers of accused at ages 5 to 9, the apparent trend should be interpreted with caution.

Figure 38 distinguishes the influence on specialization of the number of incidents in the career and the age of onset of recorded offending. In Figure 38, the proportion of specialized careers for offenders born in 1987⁵ is plotted against the age of onset, separately for offenders with 2, 3, 4, and 5 or more incidents in the career. As in Figure 36, the prevalence of specialization decreases as the number of incidents increases: for practically all ages of onset, careers with only 2 incidents have the highest levels of specialization, followed by careers consisting of 3 incidents, and so on. Although there are fluctuations due to small cell sizes, the four curves in Figure 38 generally exhibit a pattern of a decrease in the prevalence of specialization as the age of onset increases from 8 or 9 to 13, then an increase as the age of onset increases to 17.⁶ Since the curvilinear relationship, shown in Figure 37, between the age of onset and the prevalence of specialization is reproduced even after controlling for the number of incidents (Figure 38), it is not due merely to the relationship between the age of onset and the number of incidents in the career, but rather appears to be a genuine age-related phenomenon. The increase in specialization with increasing age of onset for ages of onset of 11 or more is consistent with other research, but the decrease in specialization with increasing age of onset for ages of onset of 7 to 11 (in the 1990 cohort) and 9 to 13 (in the 1987 cohort) is unexpected.

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Notes

1. In order to make the analyses more consistent with other research, offences against the administration of justice are not considered when classifying delinquent careers as specialized or versatile. For example, a person whose delinquent career included only offences against the person and administrative offences would be classified as specializing in the former. However, the presence or absence of administrative offences is noted in the analyses, as a separate dimension of specialization/versatility. This is the procedure that was adopted by research on "court careers" published by the Canadian Centre for Justice Statistics (Carrington et al., 2005).
2. The UCR2 coding scheme specifies that if an incident involves multiple criminal violations, the four most serious are to be coded, in decreasing order of seriousness. For example, if an incident involved an aggravated assault, a break and enter, and a breach of a probation order, these three violations would be coded, in the order given.
3. Careers with 13 or more incidents (for offenders born in 1987) or 9 or more incidents (for the 1990 birth cohort) are combined into one group in Figure 36, since the numbers of specialized offenders become very small (less than 10) in these high-frequency careers.
4. The breakdown of repeat offenders by cohort and age of onset is shown in Table A.3 in the Appendix.
5. The results are similar for offenders born in 1990, but are obscured by small cell sizes.
6. A decrease in specialization over the ages of onset of 9 to 13 does not occur in the curve for careers consisting of 4 incidents, but it does occur over the range from 8 to 13 years. The trends for ages of onset from 8 to 12 years in this curve and the curve for careers consisting of 3 incidents must be interpreted with caution, as there are substantial fluctuations due to small cell sizes.