There is a lack of consensus in the academic literature and among policy makers and practitioners on the definition of violent radicalisation, and current counter-radicalisation policy responses and procedures are informed by a weak and, at times, confused understanding of the motivational and structural factors underpinning such a process. The result is a variety of interventions across the EU, signalling a lack of consensus on the purposes of counter-radicalisation. In addition, indicators of success of counter-radicalisation policies are often unclear or unspecified. One consequence of this is that assessments of the effectiveness of counter-radicalisation measures and policy responses are either lacking or often methodologically questionable, impairing our understanding of the impacts of counter-radicalisation interventions on targeted communities. The article investigates problems of assessing the impact of counter-radicalisation measures using Denmark as case study. It shows how the model of radicalisation underlying the Danish counter-radicalisation efforts translate into multilayered policy objectives and diversified policy solutions, and how the initial academic and official assessments of the impact of Danish counter-radicalisation policies on end target groups following is impaired and weakened by common methodological problems and challenges. The article concludes by suggesting some ways ahead for more systematic and valid assessments of the impact of counter-radicalisation policies in Denmark and elsewhere.