Waterfall is a traditional software development methodology that follows a linear and sequential approach to project management. It is characterized by its structured and phased approach, where each phase must be completed before the next one begins.

Key principles

1. Sequential Phases: Waterfall divides the project into distinct phases, such as requirements, design, implementation, testing, deployment, and maintenance. Each phase builds upon the completion of the previous one;
2. Documentation: Extensive documentation is a key point of the Waterfall methodology. Detailed requirements, design specifications, and test plans are created at the beginning of the project and serve as the basis for each next phase;
3. Minimal Customer Involvement: Waterfall typically involves minimal customer or stakeholder involvement until the final product is delivered. Changes to requirements or design after the initial phase can be challenging and costly.

Pros and cons of using Waterfall

Pros

• Clarity and Predictability: Waterfall provides a clear project roadmap with well-defined phases and steps, making it easier to plan and estimate project timelines and costs;
• Structured Documentation: Extensive documentation ensures that project details are well-documented, making it easier for new team members to understand and continue the project;
• Quality Assurance: Accurate testing is performed after development, leading to a potentially higher level of software quality.

Cons

• Limited Flexibility: Waterfall is inflexible when it comes to changing project requirements. Any changes after the initial phase can be difficult and expensive to implement;
• Long Delivery Times: Due to its sequential nature, Waterfall can result in long delivery times before any working software is produced;
• Costly Corrections: If errors or misunderstandings are discovered late in the project, it can be costly and time-consuming to fix them;
• Not Suitable for Complex Projects: Waterfall is less suitable for projects with evolving or uncertain requirements, as it assumes that all requirements are known before the start of the project.

In summary, the Waterfall methodology is characterized by its structured, sequential approach, detailed documentation specification and scrupulous testing. It is suitable for projects with well-defined, stable requirements and where predictability and documentation are critical.