Validity in Phallometric Testing for Sexual Interests in Children: A Meta-Analytic Review

Abstract

Valid assessment of pedohebephilic interests (i.e., sexual interest in children) is fundamental to forensic clinical practice. Phallometric testing—which measures changes in penile circumference or volume, while stimuli depicting different ages and sexual activities are presented—is widely used in clinical and research settings to detect such interests. This meta-analysis summarizes studies comparing sexual offenders against children and various types of controls on phallometric tests for pedohebephilic interests (37 samples; N = 6,785) and studies examining the relationship between phallometric test scores and sexual reoffending (16 samples; N = 2,709). The findings suggest that several phallometric testing procedures are valid indicators of pedohebephilic interest. Certain methodological features of phallometric tests were associated with greater validity, such as, slide or audio-plus-slide stimuli and z-score-based indices. In addition, phallometric tests for pedohebephilic, pedophilic, and hebephilic interests predicted sexual reoffending which provides further evidence that phallometric test scores are valid indicators of sexual interest in children. In general, the interpretation of phallometric test scores as indicators of pedohebephilic interests is supported.