Which methodology involves a sequence of phases in which the output of each phase becomes the input for the next?

The Waterfall methodology is a traditional project management approach that follows a linear and sequential design process. In this methodology, the project is divided into distinct phases, where each phase is completed before the next one begins. The phases typically include requirements gathering, system design, implementation, testing, deployment, and maintenance.

The characteristic feature of the Waterfall model is that the output from one phase serves as the direct input to the subsequent phase. This means that the completion of requirements informs the design, the design informs implementation, and so on. Because of this structured progression, it emphasizes thorough planning and documentation, ensuring that all requirements are understood before moving on to the next stage. This approach is best suited for projects with clearly defined requirements and where change is minimal after the project begins.

In contrast, methodologies like Agile or Extreme programming are iterative and focus on incremental development, allowing for more flexibility and continuous improvement through feedback loops. While discovery prototyping emphasizes evolving concepts based on user feedback rather than strict phase output, the Waterfall methodology's sequence makes it distinct in how it systematically progresses through project stages.