This chapter and the one to follow are about group performance on judgment and decision-making tasks, respectively. They stand in contrast to Chapter 4, which focused on problem-solving tasks. Judgment and decision making can be distinguished from problem solving in terms of Laughlin’s Intellective-Judgmental task continuum (1980; 1999; Laughlin & Ellis, 1986). As defined in Chapter 4, collective problem solving is a cooperatively performed cognitive activity located at or near the intellective end of that continuum. This means that in principle it should be possible for group members to convincingly demonstrate to one another whether or not a proposed task response (solution alternative) is, in fact, correct. Such demonstrations depend in part on the existence-and availability to the group-of objective evaluative criteria that are enmeshed in a nexus of well-defined rules, operations, and relationships. The latter constitute the conceptual system(s) within which the problem is solved. Thus, the letters-to-numbers task involves problem-solving because proposed solutions are readily evaluated by reference to the rules of mathematics, deductive reasoning, and natural language.