This paper reviews and compares four distinct decision support system (DSS) perspectives or ‘schools’: Decision analysis, decision research, decision calculus, and implementation process. Each school represents a relatively coherent perspective for DSS development; all four address the development and use of computer-based tools that support and aid managers in their role as decision makers. They differ, however, in terms of the nature of the decision situation envisaged, the phase of the decision process considered, the primary aims for a DSS development effort, the nature of the learning to be achieved and the phase of the development process that is emphasized. The purpose of the review is an attempt to establish a more constructive approach to understanding the central tenets and challenges for DSS. At the same time, the unique concerns and distinct contributions of the different schools suggest that it is difficult to define a single approach that satisfies equally well all considerations and all demands.