“This is why you may need to blend quantitative and qualitative analysis. Our friend John Lilly likes to distinguish between “genius-driven design” (e.g., Apple) and “data-driven design” (e.g., Google). Both approaches have their strengths and weaknesses. Data-driven design is great at optimizing products with incremental changes, but it could steer you to the top of a local hill rather than the highest peak. Genius-driven design may be the only way to build a revolutionary product, but it usually needs to be supplemented with data-driven refinement”