Developing a clinically useful actuarial tool for assessing violence risk

Background A new actuarial method for violence risk assessment - the iterative Classification Tree (ICT) - has become available. It has a high degree df accuracy but can be time and resource intensive to administer. Aims To increase the clinical utility of the ICT method by restricting the risk factors used to generate the actuarial tool to those commonly available in hospital records or capable of being routinely assessed in clinical practice. Method A total of 939 male and female civil psychiatric patients between 18 and 40 years old were assessed on 106 risk factors in the hospital and monitored for violence to others during the first 20 weeks afterdischarge. Results The ICT classified 72.6% of the sample as either low risk (less than half of the sample's base rate of violence) or high risk (more than twice the sample's base rate of violence). Conclusions A clinically useful actuarial method exists to assist in violence risk assessment. Declaration of interest Research was funded by the John D. and Catherine T. MacArthur Foundation and by the US National institute of Mental Health.