Process quality costing adapted to software development

The Prevention-Appraisal-Failure and Process models of measuring quality costs, as described in BS6413, are discussed in the context of software quality costs. The Process model is selected as the better base for constructing a software quality cost model because of its suitability for application to software engineering processes. A seven-step method for modelling software quality costs is proposed and illustrated by application to a software maintenance project. Key processes in software maintenance and its quality tasks are derived from the most recently available standards-related publications. Although no results are available, a qualitative evaluation in terms of accuracy, improvement issues, measurement issues and quality costs to management concludes that the model is valid and that a greater consensus is required for identification of software quality cost elements. Implementation of quality cost measurement is not discussed save noting that there are still complex issues to be addressed.