Typing rape offenders from their offense narratives

The two leading taxonomies of rapists, Groth and Birnbaum's (1979) three-category typology and Knight and Prentky's (1990) four category typology, were explored from a combined introspective-extraspective approach (Rychlak, 1995). Twenty-five rapists were videotaped for 45 minutes while narrating their experiences and behaviors prior to, during, and after an assault. Narratives were later rated using the Sexual Offense Narrative Rating Instrument (SONRI) which contains 36 items developed from clinical experience and from the two typologies of interest. Cluster analysis of a subset SONRI items relevant to the Knight-Prentky typology resulted in four clusters similar to the four basic types specified by Knight-Prentky model. Analysis of a sub-set of SONRI items relevant to the Groth and Birnbaum's (1979) typology, identified clusters corresponding to the anger and sadistic types, but not to the power rapist type.