O’Beirne et al (2011) identified 1.4 reports of patient harm incidents per month across 19 family practices in Australia. Disagreement exists even on the best metric to capture occurrence. Responses did not converge on any one specific unit of measurement for capturing patient harm in primary and ambulatory care. For developed countries, three of the four suggested units (temporal - population; proportion of painted encounters; proportion of patients) attracted identical response numbers. For LMICs the preferred unit of measurement is proportion of patients (Figure 2.2). When asked to estimate the occurrence of patient harm using their preferred unit of measurement, responses varied greatly.