In this paper the current national legislations, the quality assurance approaches and the activities of impact analysis of three quality assurance agencies from Romania, Spain and Germany are described from a strategic perspective. The analysis shows that the general methodologies (comprising, for example, self-evaluation reports, peer reviews, on-site visits, assessment reports, follow-up measures) and main subjects of quality assurance in higher education (such as study programmes and institutional structures and processes) are very similar in the sample cases. However, up to now, impact evaluation of quality assurance has not been implemented systematically in the sample agencies (as in many others). This is the more relevant since the European standards of quality assurance in higher education oblige quality assurance agencies to analyse their general findings and observe the effects of their activities. Against that background, it is argued that methodologically sound impact analyses of quality assurance interventions in higher education institutions should be seen as an integral part of the agencies' own quality assurance because it would make their work more transparent and easier to improve systematically. The paper identifies some professionalisation needs required for impact evaluation competences: staff and peers who are qualified by methodological knowledge but also by "soft" skills such as project and conflict management.