The increased use of "regulatory science" in decision and policy making is an important component in the governance of modern states. However, contrary to what one would be tempted to assume, the use of knowledge from advisory bodies is not straightforward. Health Technology Assessment (HTA) agencies are currently preoccupied with their impact on the health care system and the examination of more active dissemination strategies. This article suggests that their influence depends on how HTA users and other actors react to an assessment, agree with or contest its content, and negotiate solutions. A continuous monitoring system is presented that could be implemented by such agencies for documenting actors' views and actions. This framework combines attributes both of self-assessment approaches and of impact assessment models.