Background Direct observation of clinical task performance plays a pivotal role in competency-based medical education. Although formal guidelines require supervisors to engage in direct... Show moreBackground Direct observation of clinical task performance plays a pivotal role in competency-based medical education. Although formal guidelines require supervisors to engage in direct observations, research demonstrates that trainees are infrequently observed. Supervisors may not only experience practical and socio-cultural barriers to direct observations in healthcare settings, they may also question usefulness or have low perceived self-efficacy in performing direct observations. A better understanding of how these multiple factors interact to influence supervisors' intention to perform direct observations may help us to more effectively implement the aforementioned guidelines and increase the frequency of direct observations. Methods We conducted an exploratory quantitative study, using the Theory of Planned Behaviour (TPB) as our theoretical framework. In applying the TPB, we transfer a psychological theory to medical education to get insight in the influence of cognitive and emotional processes on intentions to use direct observations in workplace based learning and assessment. We developed an instrument to investigate supervisors intention to perform direct observations. The relationships between the TPB measures of our questionnaire were explored by computing bivariate correlations using Pearson's R tests. Hierarchical regression analysis was performed in order to assess the impact of the respective TPB measures as predictors on the intention to perform direct observations. Results In our study 82 GP supervisors completed our TPB questionnaire. We found that supervisors had a positive attitude towards direct observations. Our TPB model explained 45% of the variance in supervisors' intentions to perform them. Normative beliefs and past behaviour were significant determinants of this intention. Conclusion Our study suggests that supervisors use their past experiences to form intentions to perform direct observations in a careful, thoughtful manner and, in doing so, also take the preferences of the learner and other stakeholders potentially engaged in direct observations into consideration. These findings have potential implications for research into work-based assessments and the development of training interventions to foster a shared mental model on the use of direct observations. Show less