Give Specific Status Reports During Projects

Today over at Web Worker Daily, they're discussing a new productivity book from Kimberly Weifling called Scrappy Project Management. It's for people trying to get stuff done as leaders in a group setting. They list several tips, including my favorite:

Provide Status Reports: "We have to communicate where are we headed and what's our progress to our goal -- so people will row like hell to get there." She advises telling the team, "You're 10% of the way, 50%, you're 75% of the way, you're 90%, you're doing good--" In return, she said, the team will actually perform 60% more efficiently than a team told to "come in every day and work like hell and do your best."

But what if you can't determine how far along you actually are in your project? I know I'm always overestimating the length of the design phase and underestimating the length of the bug-fixing phase of software projects I work on. I'm not sure what Weifling would say, but it sounds like some dissonance may be in order. If precision is a motivator for status reports, perhaps it's sometimes more important than accuracy--