**2.5 Sampling strategy**

Ten of the 74 PHC facilities in the Tshwane district were randomly selected from the list on the National Health Research Database (NHRD). All clinics in the Tshwane district appear on the NHRD. The names of the facilities were written on pieces of paper that were placed in a bowl, and jumbled. From this, the first facility was chosen. The names were jumbled again, and the second facility was chosen. The process was repeated until all ten facilities had been chosen. According to the monthly statistics, at the time of the study, an average of 300 hypertensive patients were seen in each of the ten facilities per month. Hence, a proportional sample of ten files was conveniently chosen per facility.
