Recent descriptive findings are used in the managerial decisionmaking literature to show that competitive decisionmakers do not sufficiently attend to the decision processes of others. Also, this deficiency leads to a variety of judgmental mistakes. The relevance of these judgmental mistakes is discussed in terms of major strategic decisions, as identified by Porter. The paper is concluded by offering some suggestions for the development of a revised framework of industry and competitor analysis that uses not only structural factors to explain firm conduct, but cognitive factors as well. Approximately 30 references plus 1 figure and 1 appendix. (Author abstract modified)