Inter-observer variance of examiner scoring in urology Objective Structured Clinical Examinations

The Objective Structured Clinical Examination (OSCE) is an attractive tool of competency assessment in a high-stakes summative exam. An advantage of the OSCE is the ability to assess more realistic context, content, and procedures. Each year, the Queen's Urology Exam Skills Training (QUEST) is attended by graduating Canadian urology residents to simulate their upcoming board exams. The exam consists of a written component and an OSCE. The aim of this study was to determine the inter-observer consistency of scoring between two examiners of an OSCE for a given candidate.

Thirty-nine participants in 2020 and 37 participants in 2021 completed four stations of OSCEs virtually over the Zoom platform. Each candidate was examined and scored independently by two different faculty urologists in a blinded fashion at each station. The OSCE scoring consisted of a checklist rating scale for each question. An intra-class correlation (ICC) analysis was conducted to determine the inter-rater reliability of the two examiners for each of the four OSCE stations in both the 2020 and 2021 OSCEs.

For the 2020 data, the prostate cancer station scores were most strongly correlated (ICC 0.746, 95% confidence interval [CI] 0.556-0.862, p<0.001). This was followed by the general urology station (ICC 0.688, 95% CI 0.464-0.829, p<0.001), the urinary incontinence station (ICC 0.638, 95% CI 0.403-0.794, p<0.001), and finally the nephrolithiasis station (ICC 0.472, 95% CI 0.183-0.686, p<0.001). For the 2021 data, the renal cancer station had the highest ICC at 0.866 (95% CI 0.754-0.930, p<0.001). This was followed by the nephrolithiasis station (ICC 0.817, 95% CI 0.673-0.901, p<0.001), the pediatric station (ICC 0.809, 95% CI 0.660-0.897, p<0.001), and finally the andrology station (ICC 0.804, 95% CI 0.649-0.895, p<0.001). A Pearson correlation coefficient was calculated for all stations, and all show a positive correlation with global exam scores. It is noteworthy that some stations were more predictive of overall performance, but this did not necessarily mean better ICC scores for these stations.

Given a specific clinical scenario in an OSCE exam, inter-rater reliability of scoring can be compromised on occasion. Care should be taken when high-stakes decisions about promotion are made based on OSCEs with limited standardization.