The reliability and predictive validity of a sixth-semester OSPE in conservative dentistry regarding performance on the state examination

Introduction: The aim of this study was to ascertain whether the testing format of an OSPE (Objective Structured Practical Examination) in conservative dentistry (sixth semester) predicts the scores on the practical section of the state examination (11th semester) in the same subject. Taking general student profiles into consideration (score on the school-leaving exam [Abitur], score on the preliminary exam in dental medicine [Physikum], length of university study, cohorts, and sex), we also investigated if any correlations or differences exist in regard to the total and partial scores on the OSPE and the corresponding state examination. Methods: Within the scope of this longitudinal retrospective study, exam-specific data spanning 11 semesters for dental students (N=223) in Frankfurt am Main were collected and analyzed. Statistical analysis was carried out by calculating Spearman rank correlations, partial correlations, Pearson's correlation coefficients, and multiple regressions (SPSS Statistics 21, IBM Corporation, New York). Results: The results show that the OSPE (Cronbach's α=.87) correlates with level of success on the practical section of the state exam in conservative dentistry (p=.01, r=.17). Length of university study also emerged to correlate significantly with the state exam score (p=.001, r=.23). Together, these two variables contribute significantly to predicting the state exam score (p=.001, R2 =.076). This was seen extensively among female students. It was also discovered that these female students had higher school-leaving exam scores than male students (F=6.09, p=.01, η2 =.027), and that a significant correlation between scores on the Physikum (preliminary exam in dental medicine) and OSPE scores existed only for male students (r=.17, p=.01). Conclusion: This study was able to demonstrate the predictive effect of a clinical OSPE regarding scores achieved on the state exam. Taking the limitations of this study into account, we are able to recommend using the OSPE testing format in the sixth semester during the clinical phase of dental study.