Building a Rationale Diagram for Evaluating User Story Sets

In agile methods, requirements are often represented on the basis of User Stories (US) which are short sentences relating a WHO, WHAT and (possibly) WHY dimension. They are by nature very operational and simple to understand thus very efficient. Previous research allowed building a unified model for US templates associating semantics to a set of keywords based on templates collected over the web and scientific literature. Since the semantic associated to these keywords is mostly issued from the i* framework we overview in this paper how to build a custom rationale diagram on the basis of a US set tagged using that unified template. The rationale diagram is not an i* strategic rationale diagram strictly speaking but it uses parts of its constructs and visual notation to build various trees of relating US elements in a single project. Indeed, the benefits of editing such a rationale diagram are to identify the EPIC stories in a set of US and group them around common themes. The paper shows the feasibility of building the rationale diagram, then points to the use of these consistent sets of US for iteration content planning. To ensure the US set and the rationale diagram constitute a consistent and not concurrent whole, an integrated Computer-Aided Software Engineering (CASE) tool supports the approach