Comparisons of predictive power for different morbidity measures were similar for linear and exponential models, butthe relative predictive power of the models varied with the morbidity measure. Capitation payments foran individual patient vary considerably with the different morbidity measures included in the cost model.Even for the best fitting model large differences between expected cost and capitation for some types ofpatient suggest incentives for patient selection. Models with any of the morbidity measures show highercost for more deprived patients but the positive effect of deprivation on cost was smaller in better fittingmodels