Waterfall method: what it is and what it means

The Waterfall method is a sequential approach to project management in which phases follow one another in a fixed order and each begins only after the previous one is closed: a linear sequence of phases, in which each phase is closed before the next one is opened and the project scope is defined and contracted upfront. It is effective when requirements are stable and defined upfront, that is, when you can assume that requirements are stable and known from the start; where requirements are unstable, the rigid sequence generates costly rework. It contrasts with Agile in how it handles changes during the project.

Distinctive: phases follow one another in a fixed order
Distinctive: each begins only after the previous one is closed
Distinctive: linear sequence of phases
Distinctive: defined and contracted upfront
Essential: sequential approach
Essential: requirements are stable and defined upfront
Essential: each phase is closed before the next one is opened
Essential: project scope
Constant: costly rework
Constant: requirements are stable and known from the start

Glossary

Waterfall method

A sequential approach to project management in which phases follow one another in a fixed order, each after the previous one is closed.