Hester van Eeren

| Chapter 3 3 | 36 delinquency or used to prevent juveniles committing crimes in future, for example after an adolescent has been punished under the juvenile criminal laws. Juvenile law in the Netherlands applies to adolescents aged 12-17 years (van der Laan, 2006). Not only the criminal act itself is important, but there is a strong focus on for example the background and moral development of the adolescent (van der Laan, 2006). As the present study was set up as an illustration, data was used solely to demonstrate the method. We did not aim to test the superiority of one of the interventions that were used to illustrate the method. Therefore, this article merely presents a demonstration of the relevance of a value of information analysis in the field of crime prevention and treatment. The presented input data and results should be interpreted in this context. We will start with a short summary of an earlier illustrative cost-effectiveness analysis (Schawo et al., 2012), and then introduce and illustrate the value of information analysis. Methods Interventions We compared two interventions aimed at reducing juvenile delinquency. The ‘Kursushuis’ intervention (translated and referred to as the Course House) consists of a domestic foster home where several adolescents live for about 10 months and professional care is at close hand. The treatment costs and effects were described by Slot et al. (Slot, Jagers, & Beumer, 1992). The second intervention is a systemic intervention named Functional Family Therapy (FFT), which lasts about 4 to 6 months. The costs and effects of this intervention were obtained from a multicentre quasi-experimental study in the Netherlands (van der Veldt, Eenshuistra, & Campbell, 2011). The Medical Ethical Committee of the VU University Amsterdam approved this study (number 2008/152). Cost-effectiveness model The Markov model that was used for the value of information analysis consists of three mutually exclusive model states: A) criminal behavior, B) no criminal behavior, and C) dead (Schawo et al., 2012) (Figure 1). The time horizon of the model was 20 years, with a cycle length of six months (Schawo et al., 2012). A societal perspective was taken and results were expressed as costs per Criminal Activity Free Year (CAFY) (Schawo et al., 2012). In line with health economic guidelines (The Health Care Insurance Board, 2006), the input parameters in the model were threefold. The first group of parameters were the transition probabilities. These reflect the probability that an adolescent transitions through the states. The measure of time an adolescent spends in a non-criminal state is used to estimate a CAFY. Criminal activity was based on the adolescents’ self-reported contact with the police in connection with he/she having committed one or several crimes; having had no contacts was defined as criminal-activity free and having had one or more contacts as criminally active. Transition probabilities were extrapolated until the age of 30, as we integrated parts of the long-term stabilizing effects described by