Quality Assurance (QA) is the backbone of successful software development. How you test and ensure quality is closely related to the development methodology you choose. Waterfall and Agile offer two fundamentally different approaches to QA processes, each with its own advantages and disadvantages that directly impact the efficiency and quality of your software.
In the Waterfall methodology, Quality Assurance follows a sequential structure. Testing takes place after the development phase, as a separate project phase. The development team first completes all functionalities before the software goes to the QA team for extensive rounds of testing.
This traditional approach is characterized by thorough documentation. Testers work with comprehensive test plans, test scenarios and detailed requirement documents that are created at the beginning of the project. The advantage of this is clarity: everyone knows exactly what is expected and when certain milestones must be achieved.
The testing process usually goes through these set stages:
For Dutch and Belgian organizations with strict regulations, such as financial institutions and government agencies, Waterfall QA offers the advantage of comprehensive traceability and compliance documentation.
Agile QA is all about continuous collaboration and iterative testing. Testers are part of the development team from day one and are involved in every sprint. This methodology breaks away from traditional phasing and integrates testing into the entire development process.
The difference between Waterfall and Agile in QA is nowhere more evident than in the role of the tester himself. Agile testers function as team members who actively contribute to requirements, discuss user stories and provide continuous feedback during development.
Agile Quality Assurance applies these principles:
Waterfall QA concentrates all testing activities in a specific phase after development. Agile QA integrates testing from the very beginning, with daily testing activities in parallel with development.
With Waterfall, you invest significantly in extensive test documentation before real testing begins. Agile QA works with lighter documentation, focusing on user stories and acceptance criteria.
Making adjustments is costly in Waterfall QA because changes impact the entire test schedule. Instead, Agile QA anticipates change and adapts quickly within sprints.
Waterfall often requires a larger QA team working intensively during the testing phase. Agile distributes the testing effort throughout the project with smaller, multi-functional teams.
The choice between Waterfall and Agile in QA depends on several factors. Waterfall is suitable for projects with stable requirements, strict compliance requirements and predictable environments. Many Belgian and Dutch government projects still choose Waterfall for this reason.
Agile QA is a better fit for dynamic markets, innovative products and organizations that want to respond quickly to customer feedback. Many Dutch scale-ups and IT companies in the Benelux have embraced Agile because of its speed and flexibility.
More and more organizations are adopting hybrid approaches that combine the best of both worlds. These methods, such as SAFe or Scrumfall, apply Agile principles within a broader Waterfall structure, or vice versa.
The difference between Waterfall and Agile in QA is fundamental and affects every aspect of the testing process. Waterfall provides structure, predictability and comprehensive documentation, while Agile encourages flexibility, speed and continuous improvement. No single method is objectively superior; the best choice depends on your specific project context, organizational culture and business objectives. Understanding both approaches enables you to make informed choices that optimize the quality of your software.
