COSA has been developed as a practise based approach, out of a strong belief in ethical and practical principles and was less derived from theoretical insights into sex offender relapse prevention. The call for ‘evidence based practise’, however, is growing in social intervention policies and funding, which means that interventions more and more have to provide proof that money has been well spent and goals are being met.

However, research into the implementation, outcome and possible effects of COSA is still limited. The shortage of research into COSA leaves many research questions still unanswered. Therefoe, more, and more detailed studies into effects and effective processes of COSA are needed to gather evidence of the impact of Circles in different national settings.