Design Rationale, part 1: A tale of reasons, raccoons and cat flaps

By Gordon Rugg

Often, a small example can give key insights into bigger, deeper questions. The saga of our cat flap is one of those cases. It’s an apparently trivial problem that leads swiftly into important, difficult questions like how to tackle design decisions, and how to identify design options that you might easily have overlooked, and how to spot design problems in the first place.

That’s how we ended up as one of the few the families in England to have a raccoon flap in their back door, rather than a cat flap. It’s an excellent example of design rationale – the reasoning behind a particular design decision. Like most problems involving design solutions to client requirements, it takes us into the difficult territory where human beings have trouble establishing just what they want and why they want it, and where designers are trying to find a way of tackling the problem that’s systematic but that can also capture the often messy requirements and constraints affecting a particular problem.

I’ll tell the cat flap story first, and then work through the insights that it gives about design rationale.

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