Hester van Eeren

| Chapter 2 2 | 20 Outcome measures and model parameters In order to apply health economic methods meaningfully in the field of crime prevention and treatment, we introduce a new and neutral outcome measure of cost-effectiveness modified for this particular type of intervention: criminal activity free years (CAFYs). The CAFY was defined as a measure of time spent in a dichotomous criminal or non- criminal state. When extensive data is available, criminal activity can e.g. be defined as having had police contacts or committed crimes in the past half year. For the purpose of demonstrating the model functioning and in the absence of extensive clinical data, the criminal state in this study was based on adolescent recidivism derived from clinical trial findings reported by Sexton and Alexander (2000). Transition probabilities differed according to the treatments offered. Treatment costs also differed per treatment type whereas all other costs (Table 1) in the different states were assumed to be independent of the treatment arm but dependent on the state. The cycle length used in the model was six months. This corresponds to the period common for follow up intervals in clinical trials in the field of crime prevention (Glisson et al., 2010; Henderson et al., 2009; Hogue et al., 2008). Table 1. Included types of costs Cost categories Direct Indirect Health care Medical and mental health care child (psychologist, psychiatrist, GP, specialist, ER, hospital (day) care, medication, youth welfare agency (bureau jeugdzorg)*, foster home*, residential institution, centre for addiction treatment, social worker) Medical and mental health care parent (psychologist, psychiatrist, GP, specialist, foster care*, centre for addiction treatment, social worker) Outside health care Travel expenses (incl.parking) Time spent by child on exercises as part of therapy* Time spent by parent on exercises as part of therapy* Productivity losses parent (absence from work, inefficiency at work) Informal care/ support child (community centre/ church/ moskee/ association, care/support by family or acquaintances) Criminal justice system child (Council of child protection, Bureau Halt*, Police, Lawyer, Court, Incarceration costs) Informal care/ support parent (community centre/ church/ moskee/ association) * Included until age 30