 In 1984, the first prognostic indicator for advanced non-Hodkin's lymphoma was developed.An information theory guided, computer search and evaluation procedure entropy minimax was employed to discover the largest sub-groupings for which survival is as extreme as possible In the clinical trials analyzed retrospectively and containing a large fraction of patients not matching the 'good' - of 'good' (Karnofsky status >80 and 'A" Symptoms and SGOT <36 U/L), 'poor' (Karnofsky status <70 or Night sweats) and 'intermediate' (All Remaining) prognosis patterns identified, a significant difference was found between the survival of patients with and those without a complete response to therapy.The authors concluded that trials using a patient mix weighted toward good prognosis will not find such a difference.