This report represents a set of analytic studies of patients having stages III-B and IV Hodgkin's disease who were treated with sequential therapy with single agents over a ten-year period. The objectives of these studies were to establish statistical models both for disease characterization and for patient prognosis and to compare survival of historical series with present and future series of patients. We developed a formal coding protocol to assist in reviewing the medical records of 101 patients for the collection of information such as clinical determinants, duration of critical event intervals, and treatment outcomes. The data from each patient's coding protocol were then transferred into a computerized analysis-and-retrieval system. Analysis of survival of 33 patients treated with sequential therapy with single agents revealed a median survival of 25 months for our 14 patients with stage III-B disease, and a median survival of 16 months for our 19 patients with stage IV disease. A general regression analysis model was used to develop a formula for predicting two-year survival from a prior knowledge of several clinical determinants. Currently, similar data on new patients from a randomized clinical trial study involving several hospitals are being collecred for purposes of testing the initial findings.