Does Usability Actually Sell Anything?

"Usability experts observe a few people in laboratories (not their normal environment) but turn their noses up at Web analytics that record what large, statistically valid samples actually do. Asking people what they will do is futile; they don't really know (e.g., they say that they want to eat healthy but 'supersize' their value meals). Observing people in a lab is less than optimal, since those are not true market conditions. Observing what people do under real market conditions where the real world distracts and interacts with them is a much more powerful method."