Estimate: an approximate calculation of quantity or degree or worth
Commitment: the act of binding yourself (intellectually or emotionally) to a course of action
- Estimates are not commitments.
- Plans based only on estimates are bad plans.
- Commitments based only on estimates are at best foolish, at worst dishonest.
Estimates are certainly a useful tool for making realistic commitments, but there are many others too that are equally, if not more, useful. Working at a sustainable pace, measuring data about past performance, and facilitating the genuine consensus of the whole team when committing are the way to make plans that can actually be achieved.