[owenmarshall]

Poorly! Of course, every developer/team estimates poorly without a lot of practice.

One of the biggest suggestions that has helped me create more accurate estimates: don't say that a feature/task is going to take N hours. Instead, give it a bounded rank. I use {1, 2, 4, 8, 16}. Total the rank.

That won't be helpful in the beginning, but the real win comes when you've done several projects, and you know how long 40 points will take.

I think most people are poor estimators on unbounded spaces, and this solves that problem.