Waterfall Methodology
A sequential project management approach where phases flow downward like a waterfall.
Also known as: Waterfall Model, Traditional Project Management, Linear Sequential Model
Category: Frameworks
Tags: project-management, methodologies, planning, software-development, sequential, traditional
Explanation
The Waterfall methodology is a linear, sequential approach to project management where progress flows steadily downward through distinct phases. Each phase must be completed before the next begins, like water flowing over a series of steps.
The classic phases:
1. **Requirements** - Gather and document all requirements upfront
2. **Design** - Create system architecture and detailed design
3. **Implementation** - Build the system according to design
4. **Verification/Testing** - Test against requirements
5. **Deployment** - Release to production
6. **Maintenance** - Ongoing support and updates
Key characteristics:
- Sequential progression through phases
- Extensive upfront planning and documentation
- Formal sign-offs between phases (gates)
- Changes are difficult and expensive once a phase completes
- Emphasis on comprehensive documentation
- Clear milestones and deliverables
When Waterfall works well:
- Requirements are well-understood and stable
- Technology is mature and understood
- Short projects with clear scope
- Regulatory environments requiring documentation
- Hardware projects or physical construction
- Integration with external systems requiring fixed specs
Limitations:
- Late discovery of problems (testing comes last)
- Difficulty accommodating change
- Customer doesn't see working product until late
- Assumes perfect understanding upfront
- Risk of building the wrong thing
- Long time to market
Waterfall vs. Agile:
Waterfall is often contrasted with Agile methodologies. Waterfall assumes you can know everything upfront; Agile assumes you'll learn as you go. The Agile Manifesto was largely a response to Waterfall's limitations in software development.
Modern perspective:
Few teams use pure Waterfall today in software. However, elements of Waterfall thinking (upfront planning, phase gates, documentation) are often combined with iterative approaches in hybrid methodologies.
Related Concepts
← Back to all concepts