Overview
The Sequential Legacy
Waterfall is the classic SDLC model. While widely replaced by Agile, it is still used in highly regulated industries like aerospace or medical devices.
In Waterfall, testing is often a bottleneck. Because bugs are found late, they are significantly more expensive to fix. This model relies heavily on perfect initial requirements and a rigid documentation process.
Best Practices
Dos and Don'ts
Avoid common mistakes that can lead to flaky tests and maintenance nightmares.
What to do
- •Ensure requirements are 100% frozen before moving to the next phase.
- •Use Waterfall only for projects with extremely stable, well-understood requirements.
- •Maintain a comprehensive 'Traceability Matrix'.
Common Pitfalls
- •Don't use Waterfall if the customer expects frequent updates or changes.
- •Don't ignore the high risk of 'Big Bang' integration failures at the project's end.
The Details
The QA Risk in Waterfall
From a management perspective, Waterfall creates Quality Debt. If the coding phase runs over schedule, the testing phase is usually compressed to meet the hard deadline. This leads to reduced coverage and higher 'Defect Leakage'. Modern QA teams often introduce 'V-Model' concepts into Waterfall to start verification activities earlier, mitigating this late-stage risk.