The influence of practitioner and practice characteristics on service activity levels in a New Zealand general...

The impact of practitioner and practice-related characteristics on service activity levels in general practice is assessed. It is hypothesized that while initial medical contact is largely patient-initiated and hence influenced by broader social factors, the subsequent provision of services within the medical system is more likely to be determined by organisational and professional factors. The data are drawn from a one per cent sample of all weekday general practice office encounters in the Hamilton Health District recorded over a twelve-month period from February 1979. The average encounter involved three services: typically a history or examination, a prescription and a request for follow-up. Activity levels were measured as the number of services received from the general practitioner by patients in the course of the medical encounter. The broad social characteristics of patients had little impact on activity level. Descriptors of patient health condition, and related attributes such as age and gender, were only moderately predictive of the number of services received. Practitioner and practice-related characteristics seemed to exert little influence, even after controlling for case mix. The strongest predictor of the number of services provided was the identity of the patient's doctor. Of the 30 per cent of variation in total service use explained by the model, half was accounted for by practitioner identity.