For the US: Sometimes the physician doesn't actually control scheduling, it is done by whoever owns/runs the clinic. Also, there arent scheduled gaps because lots of things need to happen when a patient shows up. So while the physician finishes up with the last patient and is doing their documentation, an MA or RN will start intake on the next patient taking them to their room, getting vitals, etc. Then the physician sees them. So even 20 min appointments are generally longer because someone might arrive on time at 1pm, then by the time they're checked in, in a room, done with vitals, it might already be 1:10. So there are like natural gaps that occur in the schedule. But I agree that the lack of transparency in the process really makes it difficult to stay on schedule. Ideally there'd be 1:1 appointment: documentation time for each patient, however payment structures are not designed for this. Instead they like to maximize the number of patients seen per day.