In 1997, a revised system was introduced at the University of Glamorgan, Wales, to assess student nurse clinical competency. This was firstly as a result of concerns that the previous system was based on limited documentary evidence, and, secondly as the Welsh National Board for Nursing and Midwifery issued new competency statements. This article reports an evaluative research study which aimed to determine whether the revised system was an effective measure of clinical competency. A series of focus groups were conducted with students, tutors and clinical preceptors to discuss their experiences of using the revised system. A content analysis was conducted of all evidence written by students to support the achievement of clinical competency. The findings of the focus groups indicated that each group had some initial problems with the assessment process. The main concern for all groups was lack of consistency and uncertainty in the assessment process. Although the introduction of written evidence to support clinical competency was welcomed, many felt that too much evidence was required. Content analysis of competency documentation aimed to compare student evidence and to determine whether there were inconsistencies in the assessment process. There were many variations in the evidence obtained from students, in particular the amount of evidence written by each student. The findings clearly indicate that further revisions are necessary to ensure that the system is implemented in the most effective way. The Fitness for Practice report (UKCC, 1999) has ensured that competency-based assessment is here to stay in the UK. Evaluative research of this type is important to ensure that we adopt the most suitable approach to assessing clinical competency.