III. Empirical Evidence
Since early in the study of crime, criminologists have been interested in the taxonomic identification of offenders. This interest dates as far back as the research of Lombroso, which attempted to define “born criminals” based on certain individual physical and psychological features (Gibbons, 1988). More recently, the study of criminal careers has brought renewed interest to whether, and to what degree, criminal offenders might concentrate, or “specialize,” in particular offense types. This gives rise to questions as to whether certain offenders engage predominantly, or exclusively, in drug offenses only, sex offenses, violent offenses, and so on. In short, research on specialization asks, can offenders be placed in distinct categories defined by their focus on particular types of crimes?
The answer to the specialization question has important implications for both criminological theory and criminal justice practice. Consequently, criminologists have made a number of explanatory propositions about the potential for specialization in offending, and empirical research has attempted to uncover its presence and nature. If there is no offense specialization, then criminologists would be wise to adhere to general explanations of crime, such as Gottfredson and Hirschi’s (1990) self-control theory, and policymakers and justice officials would be well served to treat all offenders in a similar manner based on their frequency of offending. On the other hand, findings of specialization suggest it would be prudent to consider more specific explanations of criminal behavior, such as differential opportunity theory (Cloward & Ohlin, 1960) or Moffit’s (1993) developmental taxonomy of antisocial behavior. If notions of specialization in offending are sustained, policymakers and practitioners might then look to make use of such information in developing intervention strategies and sanction structures.
Paternoster and colleagues (Paternoster, Brame, Piquero, Mazerolle, & Dean, 1998) define specialization as “the extent to which an offender tends to repeat the same specific offense or offense type on successive criminal events” (p. 133). According to Osgood and Schreck (2007), specialization reflects systematic individual differences in forms of criminal behavior engaged in by offenders. The concept of specialization may imply similarities in consecutive offenses or span an offender’s entire career (Miethe, Olson, & Mitchell, 2007). While specialization is often defined as the tendency to repeat specific types of offending, often in a direct, sequential form (see Kempf-Leonard, 1987), some believe this is too strict a definition (Francis, Soothill, & Fligelstone, 2004). Earlier studies focused somewhat more on offenses witching in consecutive criminal events or arrests, while more recent work tends to look at a particular period in time to assess the degree to which individuals exhibit a tendency to commit certain types of offenses during that time frame. Overall, specialization refers to a concentration in particular types of offenses. Clearly, the manner in which specialization is defined has important implications for theory and empirical findings.