Discussion and research show that when members of a problem-solving group engage in discussion and reach a consensus, the resultant group decision is either riskier or more cautious than the average of the individual judgments prior to the discussion. The purpose of this paper is to summarize and evaluate various theories concerning this group shift, whether conservative or risky. Aspects of shift considered are the reasons for studying group shift, the choice-shift phenomenon, personality constructs, and group impact. A bibliography lists more than 170 items related to interpersonal decision making. (JM)