An evaluation of the use of phallometric assessment for men incarcerated for sexually offending against children in New Zealand: Past results and future directions.

Phallometric assessment, the direct measurement of male sexual arousal in response to stimuli presented in a controlled setting, has been widely used in the assessment of sexual offenders to detect deviant sexual interests, determine treatment needs and inform risk assessments, but they have also been criticised due to a weak theoretical basis, wide variations in methodology and serious concerns around reliability and validity. From 1999 to 2007, phallometric assessments were conducted at two treatment units for incarcerated child sex offenders in New Zealand using a standardised Monarch 3.1 phallometric system which provided a database of 583 cases for analysis. This project, the only large scale analysis of phallometric data known to have been conducted using New Zealand data, was designed to explore a large number of research questions in three areas. The first area explored the factor structure of the assessments and the relationships between arousal profiles and a variety of co-existing demographic and offence related variables including age, social desirability, victim gender and victim age. The second area investigated the ability of a large number of possible phallometric indices to predict future both any sexual reconvictions and those involving children, with a particular focus on the role played by stimuli depicting teenagers. The third area investigated the prevalence and effects of the deliberate suppression of arousal, and analysed the ability of physiological measures to detect such suppression. The results of these investigations indicated that phallometric data factored according to the gender of the stimuli and could be further divided into age preferences resembling pedophila and teleiophilia. Phallometric indices consistently related to known victim gender but not victim age, suggesting that these offenders tended to target victims based on gender preferences but not age preferences to the same degree, posing questions about the relevance of diag