Have you ever wondered how bridges and big buildings are built? And do you know the difference between building a bridge, an airport, and a software product? The difference lies in how the workflows are managed.
Buildings, bridges, or even space programs are planned and executed in a project-oriented waterfall style. On the other hand, there are agile methodologies and frameworks like scrum that execute development in an agile way.
In this article, you will learn about the waterfall methodology in depth, including its core principles, phases, pros and cons, and how it compares to the agile methodology.
The waterfall methodology is a linear and sequential project management approach where each phase of a project must be completed before moving to the next. It emphasizes thorough documentation, well-defined project requirements, and a structured, predetermined timeline.
Waterfall is commonly used for projects with clear, unchanging requirements and minimal need for adaptability or frequent stakeholder involvement.
The waterfall methodology utilizes three core principles: sequential phases, defined requirements, and an emphasis on documentation.
The waterfall methodology is characterized by its sequential and linear approach to project management. A project is divided into distinct phases and each phase must be completed before the next one begins. The sequence ensures that there is clear progress from one stage of the project to the next.
Before beginning any implementation work, the project must move through the requirements analysis and design phase. The project must be planned and the requirements must be known and well-defined. This means a significant portion of the overall project time is spent on requirement gathering, analyzing, and documenting requirements.
The requirements can only be used as a foundation for the project plan and the execution of the project if they are well-defined. With properly defined requirements, you can test the results of each phase and ensure a certain quality to both the output of the project, as well as the project plan and project management.
An important foundation of the waterfall methodology is the emphasis on documentation at each phase. Comprehensive documentation helps with planning and executing the project.
It is needed:
The waterfall methodology comprises several distinct phases, each building upon the previous one. Understanding these phases is important for you to effectively implement a waterfall approach in your project management.
The requirements phase is the initial step in every waterfall project as it lays the foundation for the project plan and the following work. During this phase, the project team works closely with the project stakeholders and customers to gather, analyze, and document the project’s requirements and desired output.
Key activities in this phase include:
In this phase it is important to gather all the essential information for the upcoming phases, to set clear project goals, and to manage expectations by aligning with the stakeholders and customers.
After the requirements are clear and the project is planned, the project team can start with the design phase. In the design phase, the focus lies on creating a detailed design and architecture based on the defined requirements.
Key activities in this phase include:
The design phase serves as a bridge between the requirements phase and the implementation phase providing a clear “how” to the developer and the stakeholders. The developers can then follow a clear plan in the implementation phase.
Once the how is clear and the design phase is completed and approved, the team can start with the development in the implementation phase. During this phase the team begins with the actual work. This phase is where the project starts taking shape and where actual value is realized.
Key activities in this phase include:
In the implementation phase, the team needs to be careful and pay attention to details, while also adhering to the design and requirements. The output of the implementation phase must be a functional and tested product. Only when the output can be considered finished can the project move onto the verification phase.
After the implementation phase, the verification phase begins. It focuses on testing and quality assurance with the stakeholders and users. It is used to identify and rectify defects and ensure that the project meets all requirements and quality standards.
Key activities in this phase include:
The verification phase is a critical phase to ensure that the output of the project is error-free and ready to use.
The final phase of a waterfall project is the maintenance phase. This phase begins after the product is deployed and in active use by its intended users. During this phase the focus shifts to ongoing support, delivering updates and enhancements, and maybe starting follow-up projects.
Often the maintenance phase is the end of the project and only consists of one or two months of customer care. After this period the project and the waterfall ends.
Key activities of this phase include:
The maintenance phase is the end of the project and the last effort to improve the quality to evolving needs of the user.
Everything in life comes with pros and cons, and so does the waterfall methodology. It also highly depends on you, your project, and your personal experience and skill.
Especially for simple to complex projects the sequential nature of the waterfall approach provides a structured timeline and clear milestones. This helps to better understand the project and the project plan and allows stakeholders to have a reasonable expectation of when the project will be completed successfully and under what conditions.
Waterfall approaches focus on documentation and thereby ensure transparency. Even late in the project, you can understand why something happened as it happened. This can be valuable for compliance, audits, and further maintenance.
If everything is prepared well the project will have clear milestones and a plan to achieve them. This will make it easy to measure the progress of the project. This increases the transparency for the stakeholders as they can easily see if everything is still on track or not.
Transparency and the frequent milestone presentations between the phases lead to stakeholder involvement along every major step of the waterfall.
Although the stakeholders are involved in waterfall projects, they are only involved at the beginning and end of each phase and of the project. In between they have no transparency and no way to steer and give feedback, which can lead to increased project costs.
Waterfall projects also lack internal feedback between phases, which often leads to the creation of excessive documentation. This also increases costs and consumes budgets.
Because of the late feedback, the project is also less flexible to change. The later the phase and the more progress the project has made, the harder it is to change things. Stakeholder feedback typically comes late in the process, which can result in costly revisions if the project doesn’t align with user expectations.
The creation of actual value, (e.g. the time when the first code is created and deployed) is also delayed and very late in the process. This is a major risk since a lot of effort runs in the first design and requirement phases.
Major problems may not become apparent until the verification or maintenance phases, which makes it challenging to address them effectively.
If a major flaw is detected in the verification phase, or even later in the maintenance phase it is very costly to repair it since a lot of work has already been done and components typically build on each other.
The choice between waterfall and agile depends on the project’s nature, the requirements, and the organization’s culture. Waterfall is suitable for projects with stable, well-defined requirements and organizations with a preference for predictability. Agile approaches excel in dynamic environments where flexibility, collaboration, and rapid adaptation are crucial.
| Waterfall methodology | Agile approaches |
| Sequential and predictive: Waterfall follows a linear and sequential project management approach where each phase (requirements, design, implementation, testing, maintenance) is completed before moving to the next. It’s predictive, meaning the entire project plan is defined upfront | Iterative and incremental: Agile approaches are iterative, with work divided into smaller, manageable iterations or increments. These iterations allow for frequent reassessment and adaptation |
| Well-defined requirements: Waterfall requires well-documented and stable project requirements from the start. Changes are typically costly and challenging to implement once the project is underway | Emphasis on collaboration: Agile places a strong emphasis on collaboration among cross-functional teams, customers, and stakeholders throughout the project. Customer feedback is actively sought and integrated |
| Limited flexibility: The rigid structure of waterfall makes it less adaptable to changing project requirements or customer feedback. Modifications can lead to project delays and increased costs | Adaptability: Agile is highly adaptable to changing project requirements. It accommodates evolving customer needs and welcomes modifications throughout the project lifecycle |
| Late stakeholder involvement: Stakeholder feedback typically occurs at the end of the project, which can lead to misunderstandings and misalignments with user needs | Early and continuous stakeholder involvement: Agile encourages early and ongoing stakeholder involvement, ensuring that the product aligns closely with user needs and expectations |
| Longer delivery time: Waterfall projects often take longer to deliver a complete product, as the entire project is planned and executed in sequential phases | Faster delivery: Agile projects deliver working increments of the product quickly, allowing users to see results sooner. This approach supports faster time-to-market and enables feedback-driven improvements |
While Waterfall projects rely heavily on documentation and structured processes, various tools can enhance efficiency and collaboration:
Using these tools in conjunction with Waterfall methodology can streamline project management processes and improve overall project efficiency.
The Waterfall approach, with its core principles of sequential phases, documentation emphasis, and defined requirements, offers a structured approach to project management. Understanding its pros and cons is essential for making informed decisions about its suitability for specific projects.
Depending on the environment a project is executed it makes sense to choose either agile or waterfall approaches. If the environment is complicated or simple, waterfall projects deliver predictability and structure. If the environment is complex or chaotic, agile approaches are more suitable. Ultimately, the choice between waterfall and agile depends on the project’s nature, the requirements, the technology, and the organization’s culture.
Featured image source: IconScout
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