A companion piece to six-myths-of-product-development, co-authored with stefan-thomke for Harvard Business Review's online platform. Focuses specifically on the danger of mechanically transplanting manufacturing practices into product development — the central thesis of Reinertsen's "second generation lean" critique developed in principles-of-product-development-flow. Argues that manufacturing and product development have fundamentally different economics around managing-variability: in manufacturing, variability is pure waste, but in product development, some variability creates value through innovation and learning.