Estimates are tricky because different manager roles and different personalities bias toward totally different/incompatible concepts of what an estimate actually means. The author's article is conflating realistic and pessimistic estimates:
- Realistic e.g. tech managers and people who favors agile/lean/XP/etc.
- Optimistic e.g. sales managers and people who want to promote.
- Pessimistic e.g. risk managers and people who need firm deadlines.
- Equilabristic e.g. project managers and people doing critical chain
The abbreviation is ROPE, and it turns out to work really well in practice to cover all four bases. My notes are below. Constructive criticism welcome.