Dr. Donald D. Dorfman, Professor of Psychology and Radiology at the University of Iowa and a renowned expert on signal detection theory, died on April 15, 2001.

Dr. Dorfman was known for developing mathematical models based on important psychophysical theory, particularly signal detection theory. Psychophysics is a branch of experimental psychology that attempts to relate the magnitude of stimuli properties as measured by the instruments of physics and as assessed by the perceptual systems of people. Psychophysical theories try to explain how a person judges properties of stimuli. A mathematical model transforms a theory into mathematical formulas and computer programs to make predictions useful for testing the theory and to analyze and interpret data from experiments according to the theory.

Dr. Dorfman created mathematical models and computer programs to perform receiver operating characteristic (ROC) analysis that have been widely applied to experiments in which radiologists interpret medical images. He developed statistical methods of applying ROC models to experimental data that allow experiments to reach more definite conclusions. Dr. Dorfman’s mathematical models, computer programs, and statistical procedures have been used to analyze the results of hundreds of experiments on medical diagnosis. He received several grants for the National Cancer Institute to improve the evaluation of diagnostic systems.