Hester van Eeren

| Chapter 6 6 | 146 example, in estimating willingness-to-pay values, one should wonder ‘Do we want to pay only for avoiding crimes, or do we want to pay for avoiding crimes in which the costs of investigations, prosecution, witnesses, legal aid, prevention programs, and the valuation of fear are also incorporated?’ (Cohen & Piquero, 2009; Cohen, Rust, Steen, & Tidd, 2004). Though the most recent Dutch guidelines on health economic studies mentioned this shortly, if youth care overlaps with the field of criminology there could be an additional set of issues that should be given attention in research and guidelines. In sum, evaluation studies and economic evaluations studies are an important tool in further developing the content, accessibility, and affordability of youth care interventions in the Netherlands. The developments mentioned above can further direct these types of studies and can bring together clinical practice and research in youth care. Limitations Despite the strengths of the studies that are described in this thesis, such as the use of clinical practice data to evaluate the effectiveness of interventions, meaning that interventions and questionnaires were not adjusted for research purposes, and the use of an economic model to illustrate the applicability of these analyses in youth care, a number of limitations merit reflection. Firstly, the cost-effectiveness model that was introduced in Chapter 2 and further used in the value of information analysis in Chapter 3 was illustrative in the absence of underlying trial data. The analyses and interpretations illustrated how such a method could be applied when evaluating youth care interventions, specifically aimed at reducing juvenile delinquency. In applying these methods, health economic guidelines, nationally and internationally, prescribe the steps that should be taken in conducting a valid and reliable health economic evaluation study (Husereau, Drummond, Petrou, Carswell, Moher, Greenberg, et al., 2013; Zorginstituut Nederland, 2015. We were not able to follow these steps in much detail, because we only had limited data. However, future economic evaluations in youth care should take into account these guidelines and use them as a starting point to apply these methods in youth care, while different recommendations should be made for youth care specifically. Furthermore, the cost- effectiveness study in this thesis was based on methods in health technology assessment and specifically focused on cost-effectiveness analyses. However, there are alternative methods such as a cost-utility analysis, in which the effect is measured and expressed in a generic, preference weighted outcome measure like the QALY. Another alternative is a cost-benefit analysis in which the benefit is expressed in costs as well. In the US, these cost-benefit analyses are widely adopted in the evaluation of youth interventions (Aos, Lieb, Mayfield, Miller, & Pennucci, 2004). In the Netherlands, guidelines for societal cost- benefit analysis have been developed as well (Pomp, Schoemaker, & Polder, 2014). This approach, however, differs notably from the cost-effectiveness analysis presented in this thesis. If economic evaluation methods will be further applied in youth care, a uniform approach that is well documented and described is highly recommended (Dirksen & Evers, 2016).