by Carl S. Spetzler and Carl-Axel S. von Holstein

Developed in consultation with Professor Amos Tversky and Professor Daniel Kahneman (Nobel Laureate in Economics), in this paper, Dr. Carl Spetzler and Dr. Carl-Axel von Holstein present the now-de facto method for assessing probability distributions from experts. It discusses important motivational and cognitive biases, such as availability, anchoring, and representativeness, and details the assessment process to compensate for these biases, still used today with SDG’s clients.

Originally published in 1972, and reprinted in The Principles and Applications of Decision Analysis, 2004. Strategic Decisions Group, Palo Alto, CA.