Design Rationale


Even with advanced design tools, the design process typically produces a description of the desired artifact, but leaves little or no indication of the design rationale. We end up knowing what was designed, but often have no idea why it is the way it is, what motivated the particular design, what alternatives were considered and rejected, etc.

Why is this so? We believe one important answer lies in the difficulty of producing rationales and the perception of their worth. Simply put, design rationales appear, especially to designers, to be both uninteresting and more trouble than they are worth. The exciting part is designing the artifact; documentation is a mundane task. Documenting is also a lot of work, and the value in doing it typically accrues to someone else: the designer knows how the artifact works and why, so writing it all down typically provides little personal benefit. It's those who come after who get the benefit, hence the feeling among designers that rationales are more trouble than they are worth.

The irony is that designers are often delighted to describe - to one another at least - the more interesting parts of their design. We just don't know how to make it as much fun to describe those things to a design rationale capture tool.

Numerous attempts have been made to create rationale capture tools; one frequent complaint about them is that they can make the design process more work. The designer now has the additional task of creating the rationale, using a tool that is often seen as getting in the way of the design process.

Our approach to rationale capture is inspired by this set of observations and claims that a successful process must be less trouble than it is worth. The key in turn to making it less trouble is to provide natural interaction with design tools. We want designers to be able to sketch, gesture, and talk with the computer about their work in the same way they would with another designer. Our vision is a design environment with intelligence embedded in the environment, allowing designers to work in familiar ways in familiar media (e.g., whiteboards), yet give those media new and powerful capabilities (e.g., the ability to understand a sketch, ask intelligent questions about a design, etc.).

We believe this in turn offers the possibility of making rationale capture an almost-effortless, almost-incidental byproduct of design.

©2010 Design Rationale Group