The age-crime curve, with delinquency peaking during middle adolescence, has been well documented in numerous studies (Hirschi & Gottfredson, 1983; Shavit & Rattner, 1988; Steffensmeier, Allan, Harer, & Streifel, 1989; Steffensmeier & Streifel, 1991; Tittle & Ward, 1993). In general, the rate of previous offenses predicts the rate of later offenses and, in this sense, a relatively stable pattern of offending seems to exist (Overbeek, Vollebergh, Meeus, Engels, & Luijpers, 2001). Cross-sectional studies also show that adolescent delinquency diminishes after the age of 16; i.e., late adolescents frequently refrain from delinquency. Of course, individual trajectories can vary widely from the general pattern, and we must ask how normal developmental trajectories and criminal careers can be differentiated. In this respect, Farrington (1999) posed two key questions: "How far can we predict the later criminal career from the early criminal career? How are different criminal career features (e.g., age of onset, duration, frequency of offending) interrelated?" (p. 155).
Moffitt (1993) distinguishes groups of delinquents with different types of careers, more specifically life-course-persistent antisocial behavior, and adolescence-limited delinquency. The small group of consistent delinquents are at risk for continuation of their delinquent activities, while the adolescence-only delinquents are more likely to desist from further delinquent activities during late adolescence and early adulthood. Patterson, DeBaryshe, and Ramsey (1989), Loeber (1990), Moffitt (1993), Moffit, Caspi, Dickson, Silva, and Stanton (1996) have all pointed to the importance of early, pre-adolescent onset of delinquency as a distinctive feature of persistent criminality. From this thesis of early-childhood-onward chronic offenders, it follows that a group of offenders can be identified who are frequently involved in delinquency throughout adolescence. Later onset of delinquency seems to reflect a temporary disposition, and thus a higher probability of refraining from delinquency and desistance during further development. It should be noted, however, that the thesis of early-childhoodonward chronic offenders has been formulated on the basis of data from male offenders only.
Recent research by Laub, Nagin, and Sampson (1998) and Nagin (1999) has focused on the discrimination of developmental trajectories of delinquents using the data from three longitudinal studies (Glueck & Glueck, 1950; Farrington & West, 1993; Tremblay, Desmarais-Gervais, Gaspon, & Charlebois, 1987). The groups in these studies were formed on the basis of a special analysis of the available longitudinal delinquency data, using a nonparametric mixed Poisson model which takes behavior changes into account. Laub et al. (1998) used the Glueck and Glueck (1950) data to study desistance and found that the chronic offenders showed a rapid rise in delinquency during adolescence with a relatively high rate from middle adolescence on. The groups of nonchronic offenders also peaked during middle adolescence but had considerably lower levels in late adolescence and early adulthood when compared to the chronic groups. According to Laub et al. (1998) "Conditional upon having a juvenile record, the intensity of adolescent delinquency seems to be only moderately predictive of eventual desistance" (p. 232).
Nagin (1999) analyzed Farrington and West's data from Cambridge (Farrington & West, 1993) and Tremblay et al. (1987) data from Montreal. Although the Cambridge data reflect the age-crime curve, in the Montreal data Nagin found that the chronic offenders show a relatively constant level of physical aggression, without a clear increase during middle adolescence. The Cambridge data show low rates of delinquency before the age of 12. In contrast, the Montreal sample shows a different pattern, with relatively high levels for all groups at younger ages on the psychometric scale of physical aggression. …