Supportsoft Glossary

Waterfall Model for Linear Software Development

n the Waterfall model, the software development process is carried out in a very structured form. The various phases of the Waterfall model are requirements, design, development, testing, and implementation; after completion of each phase, the next phase begins. Six phases of development must be accomplished before any previous phase may be revisited. 

The Waterfall model is most effective for projects with stable and well-defined specification requirements (e.g., government, infrastructure implants, or regulated environments). The Waterfall model provides very complete documentation and enables project managers to establish timelines that enable them to manage schedules exactly. However, this effective history of service delivery is less flexible than the iterative or agile methodologies; therefore, if requirements change after the project begins development, it is difficult to accommodate those changes without contorting the project schedule or the resources needed for completion, thereby increasing the amount of time necessary to reach completion. 

Because testing occurs at the end of the development cycle in the Waterfall Model, the risk associated with a project increases if the actual deliverable does not meet the specified requirements. While the Waterfall Model has limitations, it continues to be used where extensive and accurate upfront planning is required and where compliance with any state or federal regulations is also required.