ORGANIZATIONALBEHAVIORAND HUMAN PERFORMANCE 34, 175-194 (1984) Focusing Techniques: A Shortcut to Improving Probability Judgments? BARUCH FISCHHOFF Decision Research, A Branch of Perceptronics AND MAYA BAR-HILLEL Hebrew University A recurrent finding of judgment research is that people often ignore impor- tant kinds of information, such as the base rate of some occurrence. Focusing techniques attempt to improve judgment in inferential problems by helping people to attend to all available information. One such technique is Subjective Sensitivity Analysis, which requires people to consider what judgments they would make were a given item of information to assume each of a series of possible values. A second focusing technique is Isolation Analysis, which requires people to consider what judgment they would make were each item of information to have been the only one available, prior to making a summary judgment based on all given information. In several experimental tasks, both techniques promoted the use of otherwise neglected kinds of information. Unfortunately, they also promoted usage of normatively irrelevant informa- tion. Similar effects were obtained both with a more modest technique, Min- imal Focusing, which merely instructs subjects to "attend to all the infor- mation," and a more ambitious one, Balanced SSA, which applies subjective sensitivity analysis to both items of information, rather than just to the one that is customarily ignored. All in all, the data suggest that these techniques do not actually enhance people's understanding of the role of base-rate con- siderations, but merely encourage the use of whatever information is pre- sented. Improving judgment requires more extensive education than can be imparted through mechanical employment of focusing techniques. A disturbing finding of research into probabilistic reasoning is that people often seem oblivious to certain kinds of information that play a major role in normative models of inference, most notably sample size, base rates, and predictive validity information (Kahneman, Slovic, & Support for this research was provided by the Advanced Research Projects Agency of the U.S. Department of Defense, the National Science Foundation, and the United Kingdom Medical Research Council. Please address correspondence and requests for reprints to Baruch Fischhoff, Decision Research, 1201 Oak St., Eugene, OR 97401. 175 0030-5073/84 $3.00 Copyright© 1984 by Academic Press, Inc. All rightsof reproduction in any formreserved.