Leveraging inconsistency in software development

Software engineers make use of many descriptions, including analysis models, specifications, designs, program code, user guides, test plans, change requests, style guides, schedules, and process models. But since different developers construct and update these descriptions at various times during development, maintaining consistency among descriptions presents several problems. Descriptions tend to vary considerably. Individual descriptions can be ill-formed or self-contradictory and frequently evolve throughout the life cycle at different rates. Also, checking the consistency of a large, arbitrary set of descriptions is computationally expensive. The authors assert that maintaining consistency at all times is counterproductive. In many cases, it may be desirable to tolerate or even encourage inconsistency to facilitate distributed team-work and prevent premature commitment to design decisions. They advocate using inconsistency to highlight problem areas, using it as a tool to improve the development team´s shared understanding, direct the process of requirements elicitation, and assist with verification and validation