The accuracy of age-sex registers, practice medical records and family practitioner committee registers.

This paper presents the results of a point prevalent evaluation of the comparative reliability and validity of age-sex registers, practice medical records and family practitioner committee (FPC) registers from five teaching practices. They all exhibited similar levels of acceptable accuracy for patient names, sex and age, but the distribution of wrong addresses varied greatly: practice medical records 3.9 per cent, age-sex registers 8.2 per cent and FPC registers 17.1 per cent. The presence of a patient entry in all three registers was associated with a high degree of probability (95.3 per cent) that this individual would be a bona fide practice patient. The register population inflation rates were FPC records 5.5 per cent, practice records 9.8 per cent and age-sex registers 10.6 per cent, but there were large variations between individual practices. A statistically significant contribution to inflation rates came from the age groups 0 to 1 and 21 to 40 (p<0.0005). The register population deflation rates were minimal. The significance of these findings is discussed and the need for practices to determine the accuracy of their individual age-sex registers is stressed. A convenient and economic method for so doing is suggested. We also suggest ways of making it easier to construct and use age-sex registers, since they can be a most versatile and useful aid to research in general practice.