What is Waterfall Methodology?
The Waterfall methodology is one of the best-known project management methodologies. Many organizations have used it for a long time, and many project managers (PMs) know it.
The waterfall methodology: A brief introduction
The waterfall methodology of project management involves the sequential execution of clearly defined project phases. It requires clear demarcation of these phases. A phase early in the lifecycle of the project defines and finalizes the project requirements. Subsequent phases are geared towards meeting those requirements.
The waterfall methodology originated in industries like construction and manufacturing. Winston W. Royce conceptualized the use of this methodology for software development in 1970.
Key characteristics of the waterfall methodology
The following distinct characteristics in the waterfall methodology are notable:
Phases for sequential execution
You need to have clearly defined phases in the waterfall methodology. They must be executed sequentially. You need to clearly define the boundary of these phases, e.g., entry and exit conditions. The execution of one phase can start only after the end of the preceding phase.
The sequentially arranged phases look like a waterfall. This is the origin of the name of this methodology.
Flexibility in terms of the defining the phases
While the waterfall methodology requires you to have sequentially executed phases, it doesn’t mandate any particular phase. You choose which phases you want based on your industry. Take the example of the software development industry. You can have the following phases:
- Defining the business requirements;
- Analysis of the business requirements;
- Designing the technical specifications;
- Warranty support after deployment;
- Transition to operational and maintenance teams for ongoing maintenance and enhancement.
You can have a distinct phase called “code review” between the coding and testing phases. The methodology allows that flexibility.
Let’s take another example of this flexibility. You can have a post-production deployment support phase between the deployment and warranty support phases. This helps if you expect too many support tickets right after the system goes live. Such a period needs extra support from the development team. Once you have passed this phase successfully, you can start the warranty support phase. While the warranty phase still requires the availability of the development team, you need less time from them.
Flexibility in terms of the tasks in the phases
The waterfall methodology mandates clearly defined and demarcated phases. However, the methodology doesn’t dictate the tasks within a phase. You can define the tasks based on the characteristics of your industry and projects.
Take the example of the code review phase mentioned above. You can add it to the “coding” phase if you want.
Similarly, you can include the “post-production deployment support” phase mentioned above within the warranty support phase itself. You can define different resource requirements for this task then.
Rigidity in terms of freezing the requirements
Waterfall projects typically implement stringent change management processes. After you finalize the requirements, you can change them only if you have strong reasons. Change management processes might also mandate a cost-benefit analysis before changing requirements.
Requirement changes late in the cycle can be very expensive. With its origin in the construction and manufacturing industries, the waterfall methodology is naturally rigid here.
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Room for reviews after every phase
Clearly defined and demarcated phases allow you to review the project after every phase. You can involve the relevant stakeholders in this process. These reviews allow you to make course corrections if required. You can start the next phase only when you are fully satisfied with the review. This prevents issues from trickling down the project lifecycle.
Roles in a project utilizing the waterfall methodology
The waterfall methodology has been widely used in many industries. The project manager role is common in all industries. The other roles vary greatly based on the industry.
In the software development industry, a project team utilizing the waterfall methodology can have the following roles:
- A project manager;
- A software architect;
- Business analysts (BAs);
- UI (user interface) designers;
- DevOps engineers.
Pros and cons of the waterfall methodology
The waterfall methodology offers the following advantages:
- Familiarity: It’s one of the most prominent PM methodologies. Most PMs have sufficient familiarity with it. You can easily find PMs with experience in leading waterfall projects.
- Applicability: PMs in many industries use the waterfall methodology. This methodology isn’t confined to the software development industry. It’s a common choice for projects in sectors like manufacturing and construction.
- Simplicity: Clearly defined and demarcated phases make this methodology easy to understand. Most PMs understand the concept of sequentially executed phases.
- Risk mitigation: Thorough reviews after every phase make it easy to identify and mitigate risks. PMs managing high-visibility and complex projects often prefer the waterfall methodology due to this.
- Availability of guides, tutorials, and resources: The waterfall methodology has been around for a long time, and there are extensive guides, tutorials, and resources for practitioners.
The disadvantages of using the waterfall methodology are as follows:
- Rigidity: You find it hard to change the project requirements in a waterfall project. This rigidity can make it hard to adapt to technological or other changes.
- The lack of customer involvement during the project execution: Customers get to see the final product only at a late stage in the project. The project team can’t get any customer feedback during the earlier stages.
Where can you use the waterfall methodology?
Use the waterfall methodology when you have clearly defined requirements. You can use it in projects with finalized requirements. This methodology doesn’t suit projects with fluid, unclear, and evolving requirements.
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The best training courses for the waterfall methodology are the Waterfall Project Management Course by ProjectManagers.org, the Waterfall Project Management by The Knowledge Academy, and the Waterfall Project Management Training by the Project Management Company.
The best project management tools that support the waterfall methodology are Wrike, ProjectManager, and Smartsheet.
T.E. Bell and T.A. Thayer had written a paper in 1976 about this project management methodology. They used the term “Waterfall” for the first time in that paper.