> Rather than trying to generate hypothetical ideas for "how can we make our search better", we spend a lot of time analyzing our data to find where we are failing. Many of our biggest relevance improvements have come from tracking and understanding the types of queries where we consistently fail to generate results or user engagement.

This sounds a lot like the 6-sigma approach of driving improvement by focusing obsessively on eliminating "defects".

There are certainly huge wins that can be obtained by identifying and eliminating bugs or corner-cases with undesired behavior. But it's scary to imagine a world where this is used as a replacement for innovative thinking - ie, "how can we make our search better". If Steve Jobs had focused all his proverbial efforts on minimizing flip-phone defects, the world would have missed out on the smartphone revolution.