Which model emphasizes a sequential approach to software development?

The Waterfall model emphasizes a sequential approach to software development. This model is one of the earliest methodologies used in software engineering and is characterized by its linear progression through distinct phases: requirements analysis, system design, implementation, integration and testing, deployment, and maintenance. Each phase must be completed before the next phase begins, which creates a structured and disciplined approach to software development.

The strengths of the Waterfall model lie in its simplicity and the clear documentation produced at each phase, making it easier to manage and understand. This model works well for projects where requirements are well understood and unlikely to change, as each phase must be completed before moving on to the next, preventing revisions and changes until testing and maintenance phases.

Other models, such as Agile or Spiral, incorporate iterative or flexible approaches that allow for changes and feedback throughout the development process, whereas the Waterfall model's rigid structure is its defining characteristic.