Statistical analysis
REGRESSION
The primary endpoint was analyzed using a two-tailed non-parametric Mann-Whitney test, as well as a univariate linear regression model. The same tests were used to analyze the progression curve during the four formative OSCEs.Assuming a median mark of 12/20 in the control group for the summative OSCE, an improvement of 2 points in the intervention group and a standard deviation of 2, with a total of 16 students per group, the study was estimated to have 80% power to detect such a difference, assuming two-sided tests.Multivariate linear regression models were then performed adjusted for age, repetition of the past year, and the number of students retaking exams to account for potential selection bias.To deal with the difference in sample size between the intervention and the control group, we also conducted sub-group analyses by randomly selecting 80 students among the control group, thus providing a 1:4 ratio between the intervention and control groups respectively to reanalyze the main outcome. This process was performed 5 times, to explore whether the difference in sample size between the two groups could have influenced our findings.The analyses were performed using R software (version 3.6.1), with a p value < 0.05 considered significant.