Product management glosary


What is Waterfall?

The Waterfall model is a linear and sequential approach to project management and product development. It is a traditional method that has been used in various industries, including software development, construction, and manufacturing. The Waterfall model is characterized by a series of distinct phases, each of which must be completed before the next phase can begin. This approach is based on the idea that each phase relies on the deliverables and information from the previous phase, ensuring that all requirements are met before moving forward.

History of the Waterfall Model

The Waterfall model was first introduced by Winston W. Royce in 1970 as a way to improve the software development process. Royce's original paper, "Managing the Development of Large Software Systems," criticized the then-current software development practices and proposed the Waterfall model as a more structured and disciplined approach. Although Royce did not use the term "Waterfall" in his paper, the name was later coined due to the model's visual representation, which resembles a cascading waterfall.

Phases of the Waterfall Model

The Waterfall model consists of several distinct phases, which are typically executed in the following order:

  1. Requirements: In this phase, the project team gathers and documents the requirements for the product. This includes understanding the needs of the end-users, the business objectives, and any technical constraints.
  2. Design: Based on the requirements, the team creates a detailed design of the product. This includes defining the overall architecture, user interfaces, and data models.
  3. Implementation: In this phase, the product is built according to the design specifications. Developers write code, create databases, and integrate various components.
  4. Verification: The product is tested to ensure that it meets the requirements and is free of defects. This includes functional testing, performance testing, and security testing.
  5. Deployment: Once the product has been tested and approved, it is deployed to the end-users. This may involve installing software on user devices, setting up servers, or configuring networks.
  6. Maintenance: After deployment, the product is maintained to address any issues that arise, make improvements, and provide ongoing support to the end-users.

Advantages of the Waterfall Model

There are several advantages to using the Waterfall model for project management and product development:

  • Structure and clarity: The Waterfall model provides a clear and structured approach to project management, making it easy to understand and follow.
  • Documentation: Due to its linear nature, the Waterfall model emphasizes thorough documentation at each phase, which can be helpful for future reference and maintenance.
  • Control: The sequential nature of the Waterfall model allows for greater control over the project, as each phase must be completed before moving on to the next.
  • Easy to manage: The Waterfall model is relatively simple to manage, as it requires minimal planning and coordination between phases.

Disadvantages of the Waterfall Model

Despite its advantages, the Waterfall model also has some drawbacks:

  • Difficulty accommodating changes: Due to its linear nature, the Waterfall model can be inflexible when it comes to accommodating changes in requirements or design. Any changes that arise during the project may require going back to previous phases, which can be time-consuming and costly.
  • Delayed feedback: The Waterfall model does not provide opportunities for end-user feedback until the product is nearly complete, which can lead to issues that are difficult and expensive to fix.
  • Higher risk: The risk of project failure is higher with the Waterfall model, as any issues that arise during the later phases may require significant rework and additional resources.


The Waterfall model is a traditional approach to project management and product development that offers a structured and linear process. While it has some advantages, such as clarity and control, it also has several drawbacks, including difficulty accommodating changes and delayed feedback. As a result, many organizations have turned to alternative methodologies, such as Agile, which offer more flexibility and adaptability in today's fast-paced and ever-changing business environment.