The development of an operational currency and tariff system for forensic mental health services has been underway in the United Kingdom since 2011, in line with government targets. A successful approach to the currency and tariff agenda requires both a way of capturing patient's needs and resource requirements while providing a way of evidencing outcomes to support payment. The focus of the work to date has been to establish a methodology that quantifies patient's clinical and resource needs but has yet to explore outcome methodology. In 2015, Speak, Hay, and Muncer developed a 4-factor model of the Health of the Nation Outcome Scales, which was mandated for evaluating outcomes in adult and older person services. The focus of this article was to explore the Speak et al. ( 2015) 4-factor model of the HoNOS as an approach to evaluating outcomes in a forensic inpatient population. A national pilot study of 2,468 patients was used. Confirmatory factor analysis and exploratory factor analysis techniques were employed and indicated that the Speak et al. ( 2015) factor model did not provide an adequate fit to the forensic data. A new factor structure emerged that revealed potential domains for evaluation of outcome in forensic populations.