Rich Traceability

Creating traceability through the use of links between paragraphs of documents, or between objects in a requirements database, is a great step forward for many systems engineering organisations. It enables analysis of impact, coverage and derivation to be performed, and greatly improves the requirements management process. However, the semantics of the relationship induced by such links is very shallow: when one object is linked to another, the strongest meaning it can have is “this object may be impacted by changes to the other object”. The next step in process improvement through traceability may be to encourage the use of a deeper semantics in the traceability relationship. Satisfiability, for instance, is a richer relationship, requiring the ability to explain that one user requirement may be satisfied by the conjunction of several system requirements, or by any one of a set of system requirements. This paper builds on the ideas of others to define a possible approach to richer traceability relationships, making use of textual rationale and propositional logic in the construction of traceability arguments. The underlying logic allows other, deeper kinds of analysis to be performed. The paper also discusses the way the same structures can be applied to the management of requirements for product families. The use of “exclusive or” in rich traceability provides a way of representing alternative ways of meeting sets of requirements. It can therefore be used to represent the variance in system requirements addressed by different configurations of a product range.