Oh, I just noticed that we sparred before around this post: http://000fff.org/getting-to-the-customer-why-everything-you-think-about-user-centred-design-is-wron

Oh, I just noticed that we sparred before around this post: http://000fff.org/getting-to-the-customer-why-everything-you-think-about-user-centred-design-is-wrong/ http://000fff.org/getting-to-the-customer-why-everything-you... about the exact same issue (I am Xianhang Zhang). I don't know if we're going to get any more productive the second time around. Proving usability testing works when creating a product has the same problem with proving something like agile development works. Every project is unique so you never know how things would have turned out if you did things another way. The best you're going to get is anecdotal evidence that early stage usability testing caused significant pivots around the core concept and assume that these pivots are generally positive. Much of the customer development stuff Steve Blank talks about fall into this category.