Background and aims: Variation in the adenoma detection rate (ADR) at flexible sigmoidoscopy screening has been shown to be due to variation in endoscopist performance. There are no objective methods for scoring an endoscopist's performance reliably, and the aim of this study was to develop a valid and reliable objective scoring method using video footage of screening flexible sigmoidoscopies.
Methods: In a series of five experiments, experienced endoscopists (the scorers) independently scored a sample (n = 43) of the 40 000 flexible sigmoidoscopy extubations recorded as part of the United Kingdom Flexible Sigmoidoscopy Screening Trial (UK FSST). The scoring system, the parameters scored, and their definitions evolved over the course of the five experiments. The initial visual analogue score (range 0-100) used in the first two experiments evolved into a five-point score that ranged from 1 (E, poor) to 5 (A, excellent) in the last three experiments. The final parameters scored were: time spent viewing the mucosa, re-examination of poorly viewed areas, suctioning of fluid pools, distension of the lumen, lower rectal examination, and overall quality of the examination. The first four experiments scored one individual case per endoscopist; in experiment 5, an overall score was awarded for five cases performed by each endoscopist being assessed.
Results: Scoring five cases examined by an individual endoscopist using the A-E grading system was the most reliable method (interclass correlation coefficient 0.89). Cluster analysis demonstrated that the endoscopists in the high-scoring ADR group (ADR 14.7-15.9 %) could be differentiated from those in the intermediate- and low-scoring ADR groups (ADR 8.6-12.6 %).
Conclusions: An objective scoring system for assessing the accuracy of performance at screening flexible sigmoidoscopy, based on video footage, is described. Endoscopists who might benefit from further training can be identified using this method.