This research focuses on evaluating the effectiveness of a training course in a hospital setting, using indicators of effect size and heterogeneity index. The evaluation focused on a training course in intermediate care for nurses. The course lasted 23 days and included clinical teaching at the patient’s bedside. The competencies were measured at the beginning and end of the training course, using an observation grid based on five domains: Clinical Expert, Communicator, Collaborator, Leader and Learner-Trainer. Cohen’s and Glass’s estimators demonstrated significant effects of training on the five domains while the heterogeneity index showed a reduction in behavioural disparities within the nursing group at the end of the training course. The discussion addresses issues relating to the boundaries used to interpret effect sizes.