Computer-Aided Systems Engineering Methodology Support and Its Effect on the Output of Structured Analysis

The information systems development literature indicates that there is no conclusive, empirical evidence that CASE improves the quality of system specifications or the resulting information systems. One role of a CASE tool is to serve as a methodology companion—to assist an analyst in the creation of documentation passed to succeeding phases of the life cycle, and to guide the analyst through a particular systems development methodology. A framework for comparing the level of methodology support provided by a CASE tool is proposed and applied to 27 structured analysis methodology rules. The framework contains seven levels of rule enforcement, ranging from real-time enforcement of a rule to the absence of enforcement for a rule. The methodology enforcement framework is then applied to two popular, commercial CASE tools. Each CASE tool was used by eight project teams over a two month period to construct a functional specification for a hotel information system. The goal of the study was to examine the influence on the functional specification of the level of methodology support provided by the CASE tool for each structured analysis methodology rule. Methodology errors in the system specification were noted for each structured analysis methodology rule. An analysis of the frequency of errors indicates that internal consistency rules are easily adhered to regardless of the level of methodology support provided by the CASE tool, while hierarchical consistency rules are adhered to more frequently in the presence of rigorous methodology support.