In response to local, national and international developments and challenges many countries have developed quality assurance as a new approach and institutional innovation during the last three decades. Self-assessment is considered as a base of quality assessment in higher education. First experience of implementing self-assessment by departments was in the middle of 1990s. In the early 2000s, National Education Measurement Organization has introduced self-assessment nationwide. National Education Measurement Organization efforts led to hegemony of selfassessment in the 2000s. After fifteen years these questions are raised: 1) how was the trend of implementing self-assessment? 2) Which factors affected success and/or failure as a result of implementing self-assessment? 3) What is the lost ring of quality assessment in Iran’s higher education?

The research method was qualitative-quantitative mixed method design. Data have been gathered through documents content analysis, interviews and questionnaires. Participants in the qualitative phase were self-assessment committee members while the population of quantitative phase consisted of all faculty members of departments who implemented self-assessment. Results revealed that in spite of successful implementation of self-assessment in several departments, other departments faced problems that led to delay or pause in implementing self-assessment. Conflicts in the departments as well as losing motivation by executive committee members were the main determinants of failure in implementing self-assessment.