The two models of self-assessment examined in this paper serve different functions and provide different skills and points of focus for both learners and tutors. The standard model focuses students on their own resources and knowledge in an essentially formative assessment context. Taras' model focuses on students' understanding, using the tutor's assessment skills in both a formative and summative assessment context, with the summative context taking priority. This paper presents these differences and relates them to two important issues in educational assessment--the tensions between formative and summative assessment, and the issue of the locus of power in assessment. It concludes that while both models provide necessary skills for students, the standard model is not as supportive of an integrative model of formative and summative assessment, and not as supportive of moving the locus of power from the tutor to the students.