Hester van Eeren

| Chapter 1 1 | 12 This thesis This thesis outlines two issues that follow the current state of evidence in youth care. The first issue deals with the stringent health care budgets and the municipalities being responsible for the reimbursement of interventions in youth care from January 2015 onwards. In light of these recent developments, it could help municipalities if both costs and effects of an intervention are clear and when interventions are compared on both outcomes. Therefore, this thesis addresses the issueofwhether cost-effectiveness research in the field of youth care is feasible. Chapter 2 addresses this issue by illustrating the use of a cost-effectiveness model in which Functional Family Therapy (FFT) is compared with treatment as usual (TAU). The results of a cost-effectiveness model are, however, subject to uncertainty in their cost and effects estimates. This parameter uncertainty can be reduced if we would have more information on the costs and effects. Therefore, further research could be helpful, but further research is not without costs. In a value of information analysis, as presented in Chapter 3, the value of conducting further research is estimated and the type of research that would be most useful is identified. As this type of analysis has not been applied in the field of youth care before, Chapter 3 presents an example of this analysis based on the cost-effectiveness model of Chapter 2. The second issue is raised by using available, non-randomized, data in investigating the effectiveness of interventions in youth care practice. In such designs, statistical methods can help to control for initial, non-random, differences between adolescents assigned to different treatment groups. The PS method is such a method, and it is increasingly being used in psychological research. In Chapter 4, a Monte Carlo simulation study is conducted to find out how the PS can be used in subgroup analysis. In Chapter 5, everyday practice data is used to compare FFT and Multisystemic Therapy (MST) on their effectiveness, using the PS method. Chapter 6, the general discussion, summarizes the findings of this thesis and discusses future perspectives and implications for clinical practice, policy makers, and researchers in youth care.