What works best in a general practice specific OSCE for medical students: Mini-CEX or content-related checklists?

To develop and pilot a General Practice (GPr) OSCE assessing medical students dealing with patient encounters, which are typical for GPr and to compare different measurement instruments (global ratings, content-specific checklists). A blueprint based on Entrusted Professional Activities was used to develop prototypical OSCE stations. Four stations were tested with voluntary medical students. Students were videotaped and assessed with self-developed content-specific checklists, a global rating for communication skills, and mini-CEX. Results were compared according to students' phases of studies. All three measurements were able to discriminate between clinical and pre-clinical students. Clearest results were achieved by using mini-CEX. Content-specific checklists were not able to differentiate between those groups for the more difficult stations. Inter-station reliability for the global ratings was sufficient for high-stakes exams. Students enjoyed the OSCE-setting simulating GPr consultation hours. They would prefer feedback from GPs after the OSCE and from simulated patients after each encounter. Although the OSCE was short, results indicate advantages for using a global rating instead of checklists. Further research should include validating these results with a larger group of students and to find the threshold during the phases of education for switching from checklists to global ratings.