Graduate attributes (GAs) have become a necessary framework of reference for the 21st century competency-based model of higher education. However, the issue of evaluating and assessing GAs still remains unchartered territory. In this article, we present a criteria-based method of assessment that allows for an institution-wide comparison of the various acquisition levels of different GAs. In order to achieve this, we first propose an understanding of GAs as knowledge, skills and attitude constructs, which directly impacts the operational development of GA scales. Second, after briefly discussing some shortcomings in current assessment/evaluation tests for GAs, we present the many features of the criteria-based model for assessing GAs, such as the importance of the proper interpretation of GAs as can-do statements, a theory-based development of the abstract categories that make up a scale for GA assessment and concrete examples of GA scales based on these abstract theories.