The reliability and validity of a matrix to assess the completed reflective personal development plans of general practitioners

INTRODUCTION We wished to determine whether assessors could make reliable and valid judgements about the quality of completed reflective personal development plans (PDPs) for the purpose of accrediting UK general practitioners (GPs) for a postgraduate education allowance using a marking matrix, and secondly, to plan a feasible model of PDP assessment in the context of forthcoming GP appraisal/revalidation that would overcome the main sources of error identified from this study. METHODS Within generalisability theory, a variance components analysis on PDP scores estimated reliability and the effect on them of varying, for example, the number of assessors. We investigated the construct validity of the matrix through its internal consistency and detection of differences in the quality of PDPs. RESULTS For a single PDP and one assessor, 37.6% of the variance in scores was due to true differences in the quality of the PDP. Between 5 and 7 PDP assessors are needed to achieve summative reliability of greater than 0.8. While increasing the number of judges is important, reliability could also be improved by addressing assessor subjectivity. Construct validity was demonstrated, as the matrix distinguished between good, satisfactory and poor PDPs, and it had good internal consistency. CONCLUSION PDP assessment has reasonable summative characteristics for the purpose of assessing GPs' reflective continuing professional development. If doctors could include their PDPs within their revalidation folders as evidence of their reflections on pursuing better clinical performance, we have described a reliable, valid and feasible method of external assessment.