2025-07-09T12:46:07Z

Accurate effort estimates are contingent on eliminating all sources of surprise, and software development is particularly, if not uniquely full of surprises.

Accurately estimating the effort it takes to deliver a unit of software is notoriously difficult.

Dorian Taylor

Process Model Issues

The estimate may not model all the work needed to deliver the result in a manner that the client is willing to accept.

Why is software development so difficult to estimate?