Two other bilingual researchers performed back-translation of that version. Based on the minor differences between the back-translation and the original English instrument, we adjusted the forward translation into the final Dutch version of our BFI-11. Attending physicians’ gender was considered as a confounding variable, as research showed gender differences in personality as well as in teaching performance. We created a dummy for gender, with male as the reference category. Furthermore, we used age as a confounding variable as well, because research demonstrated differences in both personality traits and teaching performance across age. For attending physicians’ specialty, we created two categories, namely surgical and non-surgical specialties. Surgical specialties included: plastic and reconstructive surgery, neurosurgery, general surgery, orthopedics, urology, ophthalmology, otorhinolaryngology, obstetrics and gynecology. Non-surgical specialties included: internal medicine, gastroenterology, neurology, cardiology, pulmonology, pediatrics, dermatology, psychiatry, emergency medicine, radiology, radiotherapy, anesthesiology, rehabilitation medicine, pathology, nuclear medicine and clinical genetics. We hypothesized that conscientiousness, extraversion, emotional stability, agreeableness and openness would positively affect teaching performance of attending physicians. In general, the results suggest that different personality traits have different – both positive and negative – effects on different aspects of teaching performance. Of all findings, both on general and specific teaching performance. As for differences between specialties, surgeons who display higher levels of openness received lower scores on their quality of giving feedback and evaluation of residents. Non-surgical attending physicians who are more conscientious appeared to perform better on evaluation of residents. This study builds on existing body of knowledge on personality traits in relation to job performance and academic performance in medicine, as well as on qualitative research findings on traits of competent teachers in medical education. This is the first study that actually empirically quantified the relations using validated personality and teaching performance measures. In addition, this was the first study to explore this topic across surgical and nonsurgical specialties. This resulted in a more nuanced and realistic view on the role of personality traits in teaching practice, as the clinical specialty yields a specific context in which personality traits might have varying costs and benefits. Personality traits were self-reported, which means that the possibility of socially desirable responses should be considered when interpreting the results. Socially desirable reporting is generally higher in situations in which favorable self-presentation is required.