The pros and cons of set-based design

Set based design is often identified as a critical Lean PD process employed by Toyota, so much so that many people have focused on it as a high leverage tool to prioritize.

What is set-based design (aka "set-based concurrent engineering")? Basically, when creating a product, multiple versions are developed simultaneously, each version being a 'set,' with variations such as on features or application (like a car being tested for a hybrid electric version and simultaneously a high horsepower gas engine). Eventually, as information on what will be most profitable in the market gets clearer and clearer, the designs will compete against one another and finally be consolidated to contain the best and most appropriate design elements from each set.

The main point of this heavy front-end work is to make expensive design commitments as late as possible. In theory this helps to achieve the highest quality iteration of the product with the best chance of market acceptance by being a product with a diverse heritage, an almost Darwinian, survival-of-the-fittest progression. The main negative is that there are specific conditions that make this succeed or fail. Using this process without meeting these conditions can be disastrous and an expensive lesson.

So where is this method best used? Well, simply consider it's origins in the automotive world and the conditions soon become apparent. Number one, you'll most likely require a very long lead time to vet all your design sets. Number two, you need multiple development teams that you can afford to assign to the same project. And finally, you need a marketplace with the pricing and volumes to justify the expenditure.

So, basically, like the Tom Hanks movie, you need to be "big." There may in fact be smaller companies that have some type of exception to make this work for them, but in general, set-based design is not a best practice that can be blindly copied or looked as a short cut to lean efficiency, it is in fact much more like the scenic route.

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