You just spent three days of a teams time over what the designer already knew.

The point of the blue-bar incident was that the designer was not correct, and a different shade of blue (which most people inside the Googleplex thought was inferior) generated measurably more revenue - more than the designer's salary, and certainly more than the time spent experimenting with different shades of blue.

The best thing about a data-driven approach is that it gives room to be wrong. And we're proven wrong all the time: basically every meeting, there's some measured data where we go "that can't be right" - and then we either discuss ways in which we might've misinterpreted it or say "Okay, assuming this is right, then what do we do?" It sounds idiotic, but really we're (humanity in general) the idiots.

I wonder if there is any research/reasoning in why one shade of blue would generate more revenue than another?

Malcolm Gladwell had an interesting podcast about people's ability/inability to express what they really mean and feel. He uses the Aeron chair as an example of a product that was despised/considered ugly but eventually embraced for it breakthrough functionality/aesthetic.

I can see how data-backed design decisions can produced locally optimized results, the "ideal" shade of blue, logo size, typography, etc.. But I wonder if on the whole, all those optimizations work together optimally, as a wholistic experience?

[edit] Gladwell's Podcast: http://itc.conversationsnetwork.org/shows/detail230.html

Well, that's the point of multi-level A/B testing. You try all of the combinations to isolate the impact of each varying feature, but you are always testing 'wholistically'. They don't just throw a green bar up there on its own and see who clicks on it.

The original article about the 41 shades of blue says that Google decided to test the 41 shades because another team pushed a slightly different shade and it performed better.

So, it looks like the designer didn't know.

I'd contend that's because most designers don't optimize for performance, they optimize for aesthetic. When those two are in conflict which should win?

It sounds like Bowman thinks the latter, while Google thinks the former. As a stockholder I'm thankful that's the company's attitude.

Assuming the designer is correct, when you have that much traffic and easy access to real data you don't need to make assumptions.