You're probably thinking of the Hawthorne effect[1]. It's like a placebo effect for productivity experiments. It basically says that when employees were being o

You're probably thinking of the Hawthorne effect[1]. It's like a placebo effect for productivity experiments. It basically says that when employees were being observed (as part of an experiment to boost productivity), their productivity would increase even if no other changes were made. So you have to control for the Hawthorne effect to see the impact of other changes. That said, the Hawthorne effect is short-term, so you could measure the impact of building willpower and habits by looking at how people perform over a year. I imagine that this has been done, but I don't know of any studies off the top of my head. [1]: http://en.wikipedia.org/wiki/Hawthorne_effect http://en.wikipedia.org/wiki/Hawthorne_effect