[jongraehl]

What's needed may just be to solicit a wide confidence interval (e.g. "this task will take between 20 minutes and 1 month, and I'm right 90% of the time recently when making such estimates"). You can drop the lower-bound part, probably.

People absolutely should be able to provide a rough estimated amount of effort for a task. The trouble is in using a single point to describe the whole probability distribution. You may be right, in that nobody seems to have a great way of soliciting a probability distribution (or even a single probability) that makes sense. Something like a 70% confidence interval bracketing the amount of effort would be useful, but not sufficient.

I also agree that even if people could describe their beliefs about the required effort rigorously, you have to wonder how much planning/analysis they should spend trying to come up with a tight estimate. An 'outside view' - http://wiki.lesswrong.com/wiki/Outside_view - could give something reasonable in cases that aren't too novel.

I think estimates will never become useless. It's just that we may decide to replace them with "time by which we'll be late only 1/6 of the time", and provide feedback and incentives for people to correct this estimate so that it's, for someone who's experienced in the domain, eventually relatively unbiased.