[rasmusei]

Well put. Could not agree more.

In fact, I think any quantitative measure of tangible results would be flawed, at least when it comes to open-ended and creative work (research, exploratory data analysis, software design, ...). In my work as a PhD student I often have a full day, damn, even a full week without any tangible result. But when the results eventually do arrive I usually realize that those seemingly unproductive hours actually were valuable, perhaps even necessary.