Variations in physician activity and general practice patterns.

The objective of this study is to identify the practice profiles of different GPs in order to test the hypothesis of heterogeneity in physician behaviour. We have established an extensive database consisting of about 4 700 GPs from two regions in France (Aquitaine and Burgundy) for the year 2000. Variables describe the volume as well as the structure of the physicians' medical activity, income level, personal characteristics, practice characteristics, socioeconomic and geographical environment. We used two complementary methods to test the heterogeneity of the behaviour of private physicians: a cluster analysis to identify different practice profiles and econometric tests to display the determinants of the physicians' multidimensional activity. Our results show that four different homogeneous groups can be identified, each one associating a physician's level of activity to his socioeconomic status. Econometric tests clearly distinguish the main determinants between the multidimensional medical activity of rural and urban GPs. We conclude with the finding that there is no uniformity in the way GPs practice medicine. The level and type of medical activity vary greatly among physicians mainly due to the characteristics of the socioeconomic environment and other individual factors. An immediate consequence is that any cost-containment measure, such as regulating fees, which applies uniformly to all GPs, inevitably results in different outcomes according to the physicians' category type.