Cognitive Processes and the Assessment of Subjective Probability Distributions

Abstract

This article considers the implications of recent research on judgmental processes for the assessment of subjective probability distributions. It is argued that since man is a selective, sequential information processing system with limited capacity, he is ill-suited for assessing probability distributions. Various studies attesting to man's difficulties in acting as an “intuitive statistician” are summarized in support of this contention. The importance of task characteristics on judgmental performance is also emphasized. A critical survey of the probability assessment literature is provided and organized around five topics: (1) the “meaningfulness” of probability assessments; (2) methods of eliciting distributions; (3) feedback and evaluation of assessors; (4) differential ability of groups of assessors and (5) the problems of eliciting a single distribution from a group of assessors. Conclusions from the analysis with respect to future work include the need to capitalize on cognitive simplification mechanisms; making assessors aware of both human limitations and the effects of task characteristics; and emphasizing feedback concerning the nature of the task at hand.