Cone of Uncertainty
Agile In A Nutshell | Undated
The Cone of Uncertainty, described by Steve McConnel, shows that at the beginning of any project we don’t know exactly how long a project is going to take.
Dealing with the cone
Pad the estimate
Size the project relatively
Be upfront and honest
Fund incrementally
The Root Cause
If you find yourself getting tripped up by the cone of uncertainty, just remember the whole point of software estimation is to determine whether the project is even possible.
Or as Steve McConnell says: The primary purpose of software estimation is not to predict a project’s outcome; it is to determine whether a project’s targets are realistic enough to allow the project to be controlled to meet them.
—Steve McConnell, Software Estimation: Demystifying the Black Art
Author = Jonathan Rasmusson (Agile In A Nutshell)