General practitioner services under Medicare

This paper examines how general practitioner numbers, bulk-billing rates and sociodemographic variables determined usage of general practitioners and services delivered over the period from 1984 to 1990. A 10 per cent sample of patient services, maintained by the Commonwealth Department of Health, Housing and Community Services, provided the data. Data were aggregated into 148 electorates. Separate regression analyses examined the determinants of the proportion of the population attending a general practitioner and of the number of general practitioner services delivered per patient. Determinants of the growth of these levels over the seven-year period were also examined. Region (metropolitan versus rural), age structure and general practitioner supply were significant factors in these analyses. Bulk-billing rates explained nine per cent of variance in patient numbers and 22 per cent of variance in service numbers after sociodemographic variables and general practitioner supply had been taken into account. The analyses suggest that bulk-billing and general practitioner supply influence the behaviour of patients and doctors and that the effect of bulk-billing is independent of indices of medical need. This implies that bulk-billing may increase service rates and this increase is not clearly directed to improving access to medically necessary services. Because no measures of treatment outcome are available. it is not possible to decide whether the effects observed represent an improvement in health care or are better seen as overuse by patients and demand inducement by practitioners.