"You can't manage what you can't measure"

"Is a maxim that is taught and believed by many... But in fact, the phrase is ridiculous -- something said by people who are unaware of how much is hidden.  A large portion of what we manage can't be measured, and not realizing this has unintended consequences.  The problem comes when people think that data paints a full picture, leading them to ignore what they can't see.  Here's my approach:  Measure what you can, evaluate what you measure, and appreciate that you cannot measure the vast majority of what you do.  And at least every once in a while, make time to take a step back and think about what you are doing."  -Ed Catmull, Creativity, Inc. page 219