1. 1983 SIR,-Dr A J Nicholls and Dr C B Brown make a valid criticism of the practice of publishing data on the survival of a group of patients selected for a particular form of treatment without indicating the total number of patients who were eligible for treatment. Unfortunately, this information was not available to us, and in our paper we asked our colleagues to refer all potential patients to us so that, even if we were not in a position to accept them, we would at least discover the extent of the shortfall in our facilities. During the period under consideration we turned away few patients, but, unless the incidence of chronic renal failure in south east England is much lower than elsewhere in Europe, our patients must have been selected to a considerable extent by the local referral pattern;J.U.L.Y.