Design decision rationale

Abstract

Design decisions crucially influence the success of every software project. While the resulting design is typically documented quite well, the situation is usually different for the underlying rationale and decision-making process. Despite being recognized as a helpful approach in general, the explicit documentation of Design Decision Rationale (DDR) is not yet largely utilized due to some inhibitors (e.g., additional documentation effort). Experience with other qualities, e.g. software reusability, evidently shows that an improvement of these qualities only pays off on a large scale and therefore has to be pursued in a strategic, pre-planned, and carefully focused way. In this paper we argue that this also has to be considered for documenting DDR. To this end the paper presents: (i) the Decision, Goal, and Alternatives (DGA) DDR framework, (ii) experience in dealing with DGA, (iii) motivators and inhibitors of using DDR, and (iv) an approach for systematic DDR use that follows value-based software engineering principles.