Samenvatting

One of the most widely implemented behavioral programs for adult offenders in the Netherlands is a cognitive skills training called CoVa. The training is an adapted version of the Enhanced Thinking Skills program (ETS). This paper reports on the findings of several impact studies on the effectiveness of CoVa and ETS. Special attention is paid to a recent study on the measured change in cognitive skills before and after the training and a recent comparative recidivism study. The majority of studies on CoVa and ETS show positive indications of the effectiveness of the training programs. In the Netherlands the effect sizes are small, but some English studies on ETS reveal large effects. The paper discusses possible explanations for this outcome and examines the relevance of the research findings for the present version of the CoVa-training.