Evaluating the validity of a Bayesian program for predicting stage in Hodgkin's disease

A Bayesian model that provides probabilistic information about the spread of malignancy in a Hodgkin's disease patient has been developed at the Tufts New England Medical Center. In assessing the model's reliability, it seemed important to use it to make predictions about patients other than those relevant to its construction. The accuracy of these predictions could then be tested statistically. This paper described such a test, based on 243 Hodgkin's disease patients of known pathologic stage. The results obtained were supportive of the model, and the test procedure might interest those wishing to determine whether the imperfections that attend any attempt to make probabilistic forecasts have gravely damaged their accuracy.