THE DISCRIMINABILITY OF RAPISTS FROM NON-SEX OFFENDERS USING PHALLOMETRIC MEASURES - A METAANALYSIS

The authors examined how well identified rapists could be discriminate d from non-sex offenders using phallometric assessments, what variable s might moderate this discrimination, and whether rapists respond more to descriptions of rape than to consenting sex. Eleven primary and fi ve secondary phallometric studies involving 415 rapists and 192 non-se x offenders were examined using meta-analytic techniques. Study effect sizes averaged 0.82 (95% confidence interval 0. 16 to 1.49). Only sti mulus set was a statistically significant moderator of effect size: St imulus sets that contained more graphic rape descriptions produced bet ter discrimination between rapists and non-sex offenders. There was a trend for stimulus sets that contained more exemplars of rape descript ions to achieve better discrimination. Also, rapists responded more to rape than to consenting sex cues in 9 of the 16 data sets and in all 8 of those using the more effective stimulus sets.