Statistical analysis
Measurement data were expressed as the mean ± standard error of the mean (SEM). The non-parametric Wilcoxon rank-sum test evaluated the difference in scores between the two groups with and without video recording in the second and third stations and the difference in video scores between experts and examiners in the second test station. The intra-group correlation coefficient (ICC) was used to evaluate the consistency of the scores of the two video examiners at each station, and the F test was used to test the hypothesis of ICC. ICC is equal to individual variation divided by the total variation with a value belonging to [0,1], where 0 indicates untrustworthy, and 1 indicates completely trustworthy. It is generally believed that a reliability coefficient lower than 0.4 indicates poor reliability, and greater than 0.75 indicates excellent reliability [