Statistical analysis

We compared the means for each step between reviewers using Student’s t test for categorical data. Statistical significance was assumed when p value was inferior to 0.05. Confidence intervals (CI) were set at 95%. For live-reviewed assessment, we calculated a Pearson’s correlation coefficient between the operative time and the score for each step. To determine the inter-rater reliability of the assessment tool items, we calculated intraclass correlation coefficients (ICCs) for three ratings: one given during the surgery by the supervisor and two given by the video reviewers. ICC estimates and their 95% confidence intervals were based on a mean-rating (k = 3), absolute-agreement, two-way random model, single measure. Values inferior to 0.5, between 0.5 and 0.75, between 0.75 and 0.9, and superior to 0.90 were indicative of poor, moderate, good, and excellent reliability respectively [5]. All analyses were performed using the Statistical Package for the Social Sciences software (version 22.0.0, SPSS Inc, Chicago, IL).