Using design explanation within the formal object-oriented method

This paper reports the results of an action research project which studied the benefits of documenting the evolution, and the rationale for the evolution, of a requirements specification. The benefits which design explanation offers designers (as documented in the literature) suggested an investigation with a view to understanding the potential contribution of the IBIS (Issue-Based Information System) approach. The paper reports an investigation into the use of ad hoc design explanation, in which design decisions were documented as they were made using the IBIS notation. This study finds both strengths and weaknesses in the approach. It reveals ways in which IBIS might be used more effectively and leads us to suggest a further study into the complementary use of ad hoc and post hoc design explanation approaches.