Within the field of Islamist extremism and in the context of disengagement and deradicalization work, there is a particularly strong societal interest in gaining insights into the effectiveness and quality management of existing measures. However, there is a significant lack of empirically validated knowledge on how deradicalization and disengagement processes unfold in detail, and how they can be positively influenced. This creates a substantial need for evaluations that address various areas of inquiry. Despite the high importance attached to evaluating interventions, especially in the realm of targeted prevention, such evaluations remain rare and are infrequently published. The shortage of empirical insights can be attributed to various structural obstacles, methodological challenges, as well as differing objectives and expectations surrounding such research. This article discusses the specific characteristics of targeted extremism prevention, which complicates impact-oriented evaluations. It also outlines the potential pathways through which such evaluations can be conducted. The conclusion highlights differing expectations between practitioners in prevention work and security authorities, offering suggestions for addressing these unique challenges.