This article addresses the choice of the most appropriate procedure for the assessment of portfolios used in teacher and lecturer assessment. A characteristic of modern assessment modes, including portfolios, is that the information they provide is often qualitative and derived from different contexts. Unambiguous, objective rating of portfolios is difficult to achieve, because the richness and uniqueness of the contents of the portfolio necessitate interpretation and taking account of the context before judgement can be passed. From this it follows that the traditional approaches and criteria for evaluating quality are no longer appropriate. We advocate the use of a hermeneutic, interpretative approach to the judging of portfolios as well as the use of quality criteria to establish trustworthiness in performing and monitoring portfolio assessment. A constructivist approach aimed at generating maximum diversity in interpretations and debate on ideas by the different stakeholders is proposed. Finally, we offer recommendations for portfolio assessment procedures for both formative and summative purposes.