> Often I'm asked for my estimate in the same meeting I first see the story
That's definitely awful. Personally when I was leading agile teams, for anything non-trivial we'd start by creating an issue to scope the individual parts of the project, frequently allocating several days to do so.
And some stuff is still mostly unscoppable. That's where Fermi estimation and the whole "How many chips can you fit in the empire state building" time deal comes into play. You have no way to really know how long something will take, but we need to allocate resources SOMEHOW, even if its completely off. An imperfect guesstimate is better than none at all.
The catch is that everyone involved has to know that its an imperfect (and potentially completely wrong) guesstimate, and it has to be revisited regularly as new information comes in. Everyone also has to be ok with restructuring the project (or even cancelling it, in extreme cases!) if we learn its completely wrong.
We recently discovered at work that an assumption/decision that was made nearly 2 years ago turned out to be totally false. The project that relied on that false assumption was about 10% in (the assumption was made long ago, but actually work started recently). We had to sit together and ask ourselves if it was actually worth pushing through the 90% (and likely regret it in a year), or agree to scrap the 10% and start over now that we know what we're doing. We have to be careful not to pull off a Vista/WinFS resource blackhole though!
That's definitely awful. Personally when I was leading agile teams, for anything non-trivial we'd start by creating an issue to scope the individual parts of the project, frequently allocating several days to do so.
And some stuff is still mostly unscoppable. That's where Fermi estimation and the whole "How many chips can you fit in the empire state building" time deal comes into play. You have no way to really know how long something will take, but we need to allocate resources SOMEHOW, even if its completely off. An imperfect guesstimate is better than none at all.
The catch is that everyone involved has to know that its an imperfect (and potentially completely wrong) guesstimate, and it has to be revisited regularly as new information comes in. Everyone also has to be ok with restructuring the project (or even cancelling it, in extreme cases!) if we learn its completely wrong.
We recently discovered at work that an assumption/decision that was made nearly 2 years ago turned out to be totally false. The project that relied on that false assumption was about 10% in (the assumption was made long ago, but actually work started recently). We had to sit together and ask ourselves if it was actually worth pushing through the 90% (and likely regret it in a year), or agree to scrap the 10% and start over now that we know what we're doing. We have to be careful not to pull off a Vista/WinFS resource blackhole though!