Cumulative sum scoring for medical students.

Context: A variety of subjective techniques are used to assess clinical skills during medical training. The objective assessment of practical skill proficiency is not currently widespread. Cumulative sum charts have been used in several branches of medicine for the audit of practical procedural success. In this paper, we describe our use of cumulative sum scoring to present and determine competency in peripheral venous cannulation for medical students.

Method: Ten medical students each performed between 50 and 65 intravenous cannulations sequentially recording their successes and failures. Cumulative sum plots were created using previously published algorithms. Modifications of the standard plot were also used to give an early warning of poor performance and to give an earlier recognition of good performance.

Results: The 'learning curve' modification demonstrated that all students achieved competence during the study, although many needed to perform more procedures than would usually be possible during their medical school training. The 'early warning' modification aided the early identification of practice that differed from acceptable standards.

Discussion: Cumulative sum scoring is an objective measure of practical procedural success and failure that can easily be used by medical students and professionals alike, to both determine competency and to facilitate the early warning of substandard practice so that appropriate training may be instigated. The principle issue affecting the utility of the technique for medical students is the number of procedures that need to be performed in order to create a meaningful plot.