This paper focuses on the outcomes of quality assurance schemes for higher education institutions. Based on a literature review, it intends to stretch out the main outcomes of external quality assurance schemes, and tries to explore the factors determining these outcomes. The previous impact studies in various national contexts are reviewed here, and based on which, the question of whether external quality assurance can really affect the inner life of universities is answered and the reasons behind it are explored. This review provides an important reference for the future impact studies.