Student-centred methods are increasingly being used to carry out learning, teaching and assessment activities in professional education. These methods underpin current curriculum design, and evidence suggests that they have been successful in reducing the perceived theory-practice gap and making professionals fit for practice in the chosen discipline. A portfolio is a common method of assessment in many programmes. A tripartite approach to assessing the portfolio, involving the student and his or her practice supervisor in the assessment process, brings together the assessment of theory and practice, and makes the process even more transparent. The tripartite approach to assessing portfolio is used in the mentorship preparation programme at the author's university, which also prepares the student to become an assessor. Thus the assessment process becomes part of the learning experience and is valued by the tutor, student and practice supervisor. This article describes a small-scale study carried out with a colleague on the use of portfolios as a tool for assessment in a short programme via a tripartite approach involving the practice supervisor, student and tutor.