Typologies of Criminal Behavior

Classification systems (taxonomies) identify the set of categories into which instances of a given phenomenon can be placed. The Stanford-Binet intelligence test is a familiar single-variable classification system: it permits the assignment of any human population to intelligence groups ranged along a scale. Populations of offenders have often been sorted into intelligence levels on the basis of this or other intelligence tests by correctional officials. A multivariate classification might sort individuals according to income, educational attainment, and intelligence; the classification scheme would include all the logically possible combinations of these three variables. In similar fashion, a multivariate system could assign lawbreakers to types defined by age, intelligence score, and current charged offense. In both of these illustrations, some of the groupings might be unpopulated, that is, no actual cases would fall within them—there may be no child molesters who are under twenty-five years of age or who have relatively high intelligence scores, even though the classification included such a pattern.

Typologies are a special kind of taxonomy in that they involve truth claims. Typologies identify groupings assumed to exist in the real world; thus, the category of youthful and intelligent child molesters noted above might be excluded from a typology constructed by a criminologist because he or she considered this pattern to be rare or nonexistent among actual offenders.

In order to be useful in causal inquiry or correctional intervention, typologies must meet several requirements. First, a typology must be sufficiently detailed and clear so that offenders can be reliably assigned to its categories. A second requirement is that the typology identify mutually exclusive types, so that actual offenders fall into only one slot. A third criterion is parsimony, that is, a relative limit in the number of types. Finally, typologies must be empirically congruent; that is, the typological description should closely fit the individuals in a given type, and the population under scrutiny should largely fall within the typology without a residual category of unclassified cases.

Typological schemes in criminology often fail to meet these four criteria, as the following review of person-centered classifications demonstrates.