New rating scale
On Friday (7 May 2021), HMPPS published a new research report aimed to develop and validate a scale of general paraphilia to be used with men convicted of sexual offences. The initial scale was developed from examination of the wider literature, and was refined via factor analytical techniques and other validation methods. The final scale had good predictive validity and has the potential to aid future programme evaluations by ensuring groups can be matched on markers of general paraphilia.
Definition of paraphilia
A paraphilia can be a defined as persistent, intense, and atypical sexual arousal pattern. Some paraphilia result in a crime if acted on, for example acting on persistent arousal to pre-pubescent children (paedophilia). Other paraphilia can be satiated with consenting partners (e.g. sexual masochism). Accurate assessment of paraphilia is essential in order to support sentence planning for men convicted of sexual offences, to support robust evaluation and to develop our understanding of how the organisation responds to the causes and influences of sexual offending.
This study aimed to develop and validate a rating scale of general paraphilia, which could be easily scored from routine or easily accessible background and offence details (predominantly OASys records). The term ‘general paraphilia’ is used to refer to the presence of one or more distinct atypical sexual interests, rather than assuming or attempting to measure a single underlying factor for different paraphilia. A 16-item scale (Scale of General Paraphilia; SGP) was produced after examination of the literature to identify factors associated with the presence of general paraphilia.
The 16 items are:
- Intrafamilial victim
- More than one victim
- Multiple sexual offences against victim(s)
- Male child victim
- Unrelated victim
- Unrelated child victim
- Stranger victim
- Non-contact sex offence
- Possession of indecent images of children?
- Extreme/sadistic violence
- Use of weapon
- Persistence after punishment
- Victim under 12 years
- Victim 13-15 years
- Victim 16+
- Number of convictions for sexual offences
This initial scale was further refined with the use of exploratory factor analytical techniques with a sample of 188 men who had all been convicted of at least one sexual offence, and who were serving a prison sentence.
The scale was further validated with the use of a range of statistical analyses. The SGP significantly correlated with scores on the sexual interests domain of a structured professional judgement tool, which itself has good predictive validity.
The researchers (Helen Wakeling, Jamie Walton, Sinead Bloomfield, Keely Wilkinson, Nicola Mathie & Adam Carter) concluded that the research was successful in producing a valid and reliable scale for general paraphilia.
The “reasonably accurate assessment of general paraphilia” can be used for research and evaluation purposes. The researchers are keen to emphasises that the SGP has not been designed and should not be used as a diagnostic measure of paraphilia. Rather, it is designed to be used as a tool which can broadly identify those who are more likely to have one or more offence-related paraphilia
A key advantage of the SGP is that it does not rely on self-report; rather, it uses factual information about an individual’s proven offence and recorded life history.
Although recorded information also has its limitations, the researchers argue (and I agree) it is more reliable than self-report, as it does not suffer from potential issues of individuals’ under-reporting or possessing a lack of insight into paraphilia.
Since this scale has been produced using a fairly small cohort, the researchers recommend that it needs testing on a much larger scale before becoming a mainstream tool.