Turing's game and the clinical significance of outcome with borderline patients at a day hospital

Clinical significance of a treatment effect is indicated when a treated patient, after discharge, cannot be distinguished clinically from a person who is functioning on some criterion level in terms of adjustment and normality. This principle is demonstrated in a questionnaire follow‐up of patients at a day hospital. Defining the criterion level, a sex‐ and age‐matched nonpatient group completed the same questionnaire. On the basis of the questionnaires, four judges independently guessed whether or not each respondent was an ex‐patient. The agreement among the judges was high, and their classification agreed with that of a discriminant analysis in eventually declaring approximately 25% of the patients to be nonpatients. A simple model was proposed to account for the judges' performance.