Speed-quality divergence in a one-handed square-knot OSCE station: implications for total-score interpretation

To describe the relation between speed, graded knot tightness, and the compensatory total score in a one-handed square-knot Objective Structured Clinical Examination (OSCE) station at one institution.

Scoring records from 449 undergraduate medical students were retrospectively analyzed. Full-mark rates were 74.2% for speed and 33.2% for tightness, a 41.0-percentage-point ceiling contrast. Among the 433 students (96.4%) who met the 60% passing threshold (≥ 15/25), 284 (65.6%, 95% confidence interval [CI] 61.0-69.9) scored below the stringent 5/5 tightness ceiling, a rubric-defined rather than clinical bar. The most concerning rubric-defined subgroup comprised the 25 passers (5.8%, 95% CI 3.9-8.4) who received 0/5 ("clearly visible gap"), although this category has not been validated as a patient-safety endpoint. At a 70% threshold, 61.7% (95% CI 56.7-66.4) remained below the ceiling. In the pooled binary model, T4 had the largest odds ratio; its positive association persisted in both station/rater groups, although its magnitude differed and it was not the largest association in Station A. T4 is a marker, not a causal lever. This single-center finding is hypothesis-generating; multi-site, multi-rater validation is required.