We knew that couldn't possibly be right, so we doubled the estimate and tripled the team, and ended up with 6 people for 18 months - which ended up being almost exactly right.
[1]: We were moving from a dead/dying framework and language onto a modern language and well-supported platform; I think we started out with about 1MLOC on the old system and ended up with about 700K on the rewrite.
One of the hardest problems with estimating for me is that I mostly do really new tasks that either no one wants to do because they are arduous, or no one knows how to do yet. Then I go and do them anyway. Sometimes on time, mostly not. But everybody working with me already knows, that it may be long, but I will achieve the result. And in rare instances other developers ask me how did I managed to find the bug so fast. This time I was doing something I have never before done in my life and I missed some code dependencies that needed changing when I was revieving how to do that task.
software is only tougher to estimate if incompetent people (vast majority of the industry, like 4+ million) is doing the estimating :)
> software is only tougher to estimate if incompetent people (vast majority of the industry, like 4+ million) is doing the estimating :)
No, it is tough to estimate, but not only for incompetent people. And "incompetent" can be stretched to "don't know what he's doing", which is how I operate most of the time. I don't know what really needs to be done until it's done. Main part of my work is research on what actually needs to be done, then "just" implementing it. If I waited with estimating until I know what needs to be done, I would spend 3/4 time estimating and then 1/4 with clear understanding and good schedules (example description: I will be clicking keys for 5 hours).
Tangent, but I have at least 3 friends that would've (in retrospect) been nothing short of ecstatic if their home construction had "only" slipped 6 months on a 2 year timeline.
Saying incompetence is the reason is a trivial rebuttal that ignores the central claim about complexity. It’s like saying “the reason why we don’t have a theory of everything is because we don’t have competent physicists”