Prediction of general practice workload from census based social deprivation scores.

STUDY OBJECTIVE: The aim was to compare the ability of census based social deprivation scores devised by Jarman, Carstairs, and Townsend to predict workload in general practice. DESIGN: This was a prospective study of 140,050 patients registered with general practices over one year from 1 July 1981 (Third National Morbidity Survey). Main outcome measures were workload score for each patient, defined as a weighted sum of consultations at the surgery and consultations elsewhere, excluding preventive procedures. SETTING: 25 general practices in England and Wales. MAIN RESULTS: In multivariate analyses the Jarman, Carstairs, and Townsend indices all predicted workload, but the Townsend index was the best predictor, with both housing tenure and car ownership being strong predictors of workload. The overcrowding and geographical mobility variables used in the Jarman index did not predict increased workload. The weighting assigned to children under five by the Jarman index underestimated the additional workload this group generated. CONCLUSIONS: For identifying social pressures on general practice workload the Jarman index is less valid than other census based scores because it fails to include car ownership and housing tenure. A more rational scheme for compensating general practitioners would directly weight the capitation fee for children aged under five years and allocate current deprivation payments according to the Townsend index or a similar score. This would redistribute resources from London to deprived areas in northern England.