Predictive validity of the HCR-20ᵛ³ for arson recidivism

In the absence of a valid risk assessment tool for adult firesetting, practitioners often use general or violence risk assessment instruments to assess risk of future firesetting. This study aimed to examine the predictive validity of the Historical Clinical Risk Management-20 Version 3 (HCR-20ᵛ³) for arson recidivism. A pseudo-prospective design was used, with risk assessments scored from file review in a sample of 75 participants assessed for firesetting at a community forensic mental health service in Victoria, Australia between 2003 and 2015. Participants were followed up using police records for a median of 5 years (range: 8 months to 12.6 years; interquartile range: 2 to 7 years). Seven participants (9.3%) received a further arson-related charge. Time-dependent analyses indicated that in the first two years post-assessment, a HCR-20V3 Future Violence/Case Prioritisation judgement of high risk showed good predictive validity for future arson. These findings offer preliminary support for the use of the HCR-20ᵛ³ Future Violence/Case Prioritisation judgement to identify individuals who may be at an elevated risk of arson reoffending in the first two years post-assessment. However, significant methodological limitations mean results must be interpreted with caution and require replication. Furthermore, application of the HCR-20ᵛ³ to firesetting requires informed adaptation and consideration of fire-related factors.