Completeness and Consistency of the System Requirement Specification

Although the System Requirement Specification, as a first formal and detailed document, is the base for the software project in classic software methodologies, there is a noticeable problem of assuring the completeness of this document. The lack of its completeness causes uncertainty of the project foundations. This was one of motivations for agile methodologies – if the SRS cannot be easily validated, if it can change in late project phases, then get rid of the SRS. Replace formal requirements with user stories. However user stories are also requirements mostly functional requirements. As agile methodologies focus on functional requirements, it is easy to forget quality requirements. In this paper we show the impact of quality requirements analysis on functional requirements exploration. Although in our experiment we noticed considerable large functional requirements increment, we went further and examined the impact of SRS consistency on its completeness. The research has shown that the increment of the revealed requirements count may be almost three times greater, compared to the standard requirement specification method.