I found this short essay by interaction design pioneer Bill Buxton that spoke to the difficulty of defining design compared with the relative ease of defining a clear distinction between a sketch and a prototype. I found Bill's discussion useful, as I hadn't thought the two were all that different. Bill writes:
"Essentially, the investment in a prototype is larger than that in a sketch, hence there are fewer of them, they are less disposable, and they take longer to build."
What I was happy to find was that both sketch and prototype are pieces or, according to Bill, phases in the design process. More to the point, Bill's thoughts validate the consistent core to the act of designing -- which is the ability to fail in a productive way to end up, eventually, at a successful solution. Sketching is a kind of failing to come to a clear, single outcome; prototyping is a kind of failing to realize a final solution.
Bill's right. The difference between a sketch and prototype is a matter of where you want to put risk. To make a sketch presents a lower risk, but embodies higher risks because the sketched idea may be untested and unviable. To make a prototype presents a higher risk (due to production costs), but embodies loser risks because the prototyped idea can be tested for viability.
Designers iterate. They make mistakes in order to discover the next best step. They fail to succeed. But in most fields, and especially in business, failure is not an option. The latest generation of designers give much greater consideration to placement of risk than their counterparts from a few decades prior. Digital media has given us the ability to blur the line between sketches and prototypes in some cases. It's easier to fail faster, and to iterate more quickly towards a desired outcome.
Case in point, everything I am writing here is a sketch. Of thoughts. I am still far, far away from figuring things out. I continue to wonder, what is design? -JM