[netghost]

I think that one of the major problems people have when giving estimates is that developers realize there is a lot of uncertainty add in all of the "'making $#@! up' fudge factors, technical hurdles, cogitation and exploration time, etc.", and then managers mentally strip it out.

The frustrating thing is that it means the uncertainty gets lost, and people just end of with a number, which managers may treat a fact, not an estimate. That's why I think it's a really good idea to give a range including both a low and a high estimate so you can let people know: "If everything goes right, it might take two hours", but warn them that: "It could take 4 days". Once people have that kind of information, they can make much more resilient plans.

That's why we always tell our CEO that it will take 2-4 hours or 4h-5d, and let me tell you, he appreciates knowing when we don't know, because a layer of false certainty is removed.