Treatment evaluation within youth forensic mental health care is primarily focused on recidivism rates and symptom reduction [1, 2]. For individual evaluation purposes, recidivism rates are not very enlightening because they are measured after treatment and are not related to therapy progress of the individual patient. Though symptom reduction is important for hospitalized youngsters, gaining insight into the improvement of their every day life skills and insight in their offence(s) is also important. Changes in these so-called dynamic variables are considered to prevent the individual from reoffending [3, 4].
Group workers and nurses play an important role in facilitating change in dynamic variables. Van der Helm and colleagues  recently stated that 'support provided by group workers or staff, which builds on meaningful relationships and responsivity to the specific needs of each individual inmate, sets the groundwork for successful rehabilitation according to the 'Risks-Needs-Responsivity' principle.' So far, an instrument to measure behavioral functioning by group workers or nurses, however, is not available for youth forensic psychiatry. This article therefore focuses on the evaluation of an instrument to assess behavioral functioning: the Forensic Inpatient Observation Scale (FIOS; [6, 7]). This instrument not only assesses psychiatric symptoms but also oppositional behavior and attitude towards offenses. Furthermore, the FIOS can be used to observe all forensic psychiatric patients and is not limited to a specific subgroup of offenses or diagnoses. Moreover, it refers to general behavior relevant to leading a life that is acceptable in society .
A major advantage of the FIOS is that it is a nurse-rated assessment tool of which not many exist in forensic psychiatry. The instruments that are available often focus on specific behavior such as aggression (e.g. Staff Observation Aggression Scale ; Observation Scale for Aggressive Behavior ) or are primarily developed for adult forensic psychiatric patients (e.g. Behavioral Status Index ). The use of a broader observation by ward staff working in close contact with patients is important since it offers insight into actual behavior as shown during the day. Often, behavior is measured using measures such as the Youth Self Report, the Adult Self Report and/or the Teacher Report Form [11, 12], which might give conflicting results. Florsheim and colleagues , for instance, examined the role of working alliance in the treatment of delinquent boys focusing on clarifying the relation between therapeutic process and behavioral change. They used the Teacher Report Form (TRF) and the Youth Self Report (YSR) to describe the behavioral change. The TRF was filled in by ward personnel. The results from the TRF indicated changes on externalizing as well as on internalizing behavior that were related to long-term outcome. For boys, on the other hand, only changes on internalizing behavior were related to long-term outcome.
The aim of the present study was to evaluate the psychometric properties of the Forensic Inpatient Observation Scale (FIOS). More specifically, the study aimed to discover:
1. Whether the original factor structure of the FIOS, based on an adult sample, can be replicated in a sample of adolescents.
2. Whether the FIOS demonstrates adequate reliability and (convergent and divergent) validity in a sample of adolescents.