In practice disciplines, such as nursing, there has been increasing concern about examinations, which, it is argued, are problematic, since nurses' performance in written examination appears to bear little relationship to their level of proficiency in the clinical setting. To be realistic, nursing examinations have to be closely related to what the nurse does in practice. The Problem-Solving Case History, the development and evaluation of which forms the basis of this thesis, was, therefore, developed as a written simulation test involving the care management of a group of patients during a span of duty. The test confronts students with the kind of information they have to interpret and act upon in the clinical situation. This requires them to recall the principles of nursing care in a way similar to real-life. This study concerns the description and validation of the Problem-Solving Case History. Both qualitative and quantitative approaches are used to evaluate its implementation and to investigate its validity and reliability. A variety of methods was used to collect data for the validation. The methods include thought verbalisation, semi-structured interviewing, questionnaires and statistical tests of reliability. Answers are sought to the following questions: • How valid and reliable is the PSCH in testing problem-solving skills? • Can the PSCH test be used as a measure of professional competence? • Does the PSCH simulate the 'real-life' situation or event? • How reliable is the judgement made by markers of the students' performance? There is evidence, from the data analysed, that the PSCH seems to have clear application in nursing education and that it is closely related to practice. Data have elicited the use of problem-solving skills and the individual differences of approach to common tasks. It is recognised that professional competence can never be assessed fully without the inclusion of performance assessment in the work-place. Nevertheless, written papers will always have a part to play in assessing professional competence.