Waterfall

A sequential project approach where each phase (requirements, design, build, test, release) finishes before the next begins. The opposite of iterative methods like Agile.

When you'd see it: Project planning, especially in regulated or fixed-scope work like construction, hardware, and government contracts. Often invoked as the contrast when someone argues for Agile.

Why it matters: Waterfall is predictable and easy to document, but it commits to a plan before you learn anything. When requirements change mid-project, the cost of that rigidity shows up late, when it is most expensive to fix.

Common mistakes: Treating Waterfall as obsolete. It still fits work with stable, well-understood requirements and a high cost of change.

Related Agile, Gantt Chart, Critical Path