Observation of residents by supervisors is a highly recommended, but underused educational tool in postgraduate medical education. Observation can be performed indirectly (using video recordings of residents performing clinical tasks) or directly (supervisor is present when the resident performs the task). The choice of the observation method depends on aim and context of the observation. In general practice, patients tend to involve the supervisor when the resident performs the consultation. They value such participatory direct observation because they know the supervisor and appreciate their input. For specific residents' learning aims (e.g. consultation efficiency), it may be more useful if the supervisor takes a "fly on the wall" approach. Supervisors wishing to take a "fly on the wall" approach to direct observation need to inform the patient about their role and position themselves outside the patient's field of view. Indirect observation by reviewing video-recorded consultations is an alternative for this purpose.