Object-oriented approaches have received attention in management information systems development due to the advantages over the traditional approaches claimed by the proponents of the object-oriented approaches. To describe how people actually perform object-oriented analyses, this paper formalizes an object-oriented systems analysis approach. Protocol analyses of seven systems analysts, who were experienced with structured analysis, were used to formalize procedures for object-oriented analysis. The protocol analyses revealed four fundamental types of object classes in a management information system. They are: input, output, physiomorphic, and event object classes. The identification of input, output, and event classes depends upon the problem domain being analyzed. Physiomorphic classes, on the other hand, are more likely to match a schema that is perceived by the analyst based on his a priori knowledge about the problem domain classes. The protocol analyses also revealed that object classes are identified in an ad hoc manner; however, when checking the analysis, depth-first or breadth-first searching methods are often used. These, in turn, are controlled by a global backward or forward tracing strategy. Tracing the origin of data in messages was the strategy used for checking the completeness of the analysis. An experiment was conducted to compare the protocol-based object-oriented method and structured analysis. Thirty-two students who had no previous systems analysis experience were trained and then completed a problem using both techniques. The protocol-based method produced analyses that more closely matched the problem. Furthermore, it required less time to complete an analysis, and it was perceived as easier to use by the participants than the structured analysis method.