Cone of Uncertainty

The Cone of Uncertainty is a concept from the field of evolutionary and adaptive planning in software development estimations.

Due to early requirements change and other factors, there is an initial phase of high uncertainty, which drops as time passes and information accumulates. This has been called the cone of uncertainty

with evolutionary and adaptive planning it is not the case that estimates and schedules are forever unbounded or unknown. Yet, due to early requirements change and other factors, there is an initial phase of high uncertainty, which drops as time passes and information accumulates. This has been called the cone of uncertainty by McConnell in Software Estimation: Demystifying the Black Art.

The iterative response to this uncertainty is to defer an expectation of semi-reliable estimates for cost, effort or schedule until a few iterations have passed. Perhaps 10% to 20% into a project.
Relation to my thesis: finding ways to represent uncertainty