Matched controls in surveys of the use of general practice: Another use for research practice age-sex registers

This paper describes how an age-sex register may be used as a sampling frame for the selection of matched controls in studies of the use of general practice. It discusses both the analysis of data collected in this way and the advantages and limitations of the method itself. The application of the method to a case-study suggests that patients who use hospital accident departments are also high users of general practice. Although care is needed in the interpretation of such results, it is concluded that matched controls can be used to ameliorate some of the problems of research in general practice.