The waterfall model breaks down project activities into linear sequential phases. Each set of circumstances depends on the deliverables that came from the previous step as it corresponds to a specialization of task-oriented approaches. This method is typically seen in the areas of construction development and engineering design because each step must get fulfilled before the next one can follow.
Progress typically flows downwards, like a waterfall, through the phases of conception, initiation, analysis, and more. It creates a highly-structured physical environment where design changes would become prohibitively more expensive as the project moved further along.
The first known use of the waterfall model occurred in 1956 at the Symposium on Advanced Programming Methods for Digital Computers. A presentation by Herbert Benington during that series of meetings would get republished in 1983 to explain the concept. A 1970 article by Winston Royce also receives credit for using this approach, although the term wasn’t used.
Several waterfall model advantages and disadvantages are worth considering when there is a development approach to consider.
List of the Advantages of the Waterfall Model
1. It uses a clear structure.
The waterfall model uses a clear and defined set of steps to follow when compared with other methodologies. Its structure is simple because every project must go through the same sequence of events. That includes gathering requirements and documentation, system design, implementation, testing, delivery, and maintenance. A team must complete the entire step before moving to the next one, causing any roadblocks in the way to get identified immediately.
Half-finished projects are less likely to get set aside when using the waterfall model because of the need to progress through each set of steps. You’re more likely to receive a polished and complete work at the end of the experience.
2. The progression of the waterfall model is intuitive.
Unlike other methodologies that get used for development, the waterfall model doesn’t require specific training or certifications for employees or project managers. You can jump right into the system without needing to go through a steep learning curve that could slow down individual progress. That makes it one of the most intuitive systems that’s available to use today, especially since the structures promote consistency within the team.
3. The waterfall model determines the end goal early.
One of the defining advantages of using the waterfall model is that it commits to the end goal, product, or deliverable from the beginning of the process. Teams are encouraged to avoid deviation from that commitment. When you have small projects with clear goals, then this benefit allows everyone to be aware of what the intended outcome is supposed to be from the beginning of the project. That means there is less potential for getting lost in the details of daily activities as each step moves forward.
The focus of the waterfall model is always on the final goal. When your team has a concrete definition of what it hopes to accomplish with a specific deadline in mind, then this approach eliminates the risk of getting bogged down.
4. It transfers information in superior ways when compared to other methodologies.
The waterfall model’s approach is highly methodical. It emphasizes a clean transfer of information at each step to ensure that the transitions are smooth and effective. When this benefit gets applied in non-traditional settings like software development, then a new group of people are entering into the project. Documenting the lifecycle of the project at each step will ensure that everyone has a better chance of staying on the same page.
When you use the waterfall model, then the priority is to have information access that is as clean and accurate as possible. That makes it easier for new additions to the team to get caught up quickly.
5. The waterfall model keeps a project to a specific timescale.
The phased development cycles in the waterfall model enforce discipline for the work a project requires. Every phase provides a clearly defined starting point and a conclusion for teams to follow. That makes it easier for leaders to manage the progress of each step to ensure everything proceeds as expected. This benefit works to reduce any slippage that can happen in other methodologies from the agreed-upon timescales.
6. There are fewer financial surprises with the waterfall method.
Because the waterfall model requires a specific outline of each phase, the financial expectations of every task have more accuracy. Teams can estimate the time, labor, and monetary costs of each task with greater specification once everyone has defined the requirements of the project at each step. This level of detail makes the needs and outcomes of the project clear to everyone, even if some teams don’t enter until the latter 50% of the work because of their roles in this methodology.
7. It reinforces good testing habits.
Since the waterfall model uses an outlined approach in each phase, the testing steps receive prior planning before implementation. This benefit allows a team to structure their best practices into the solution before any of the work every occurs. It creates an organized, disciplined approach to a step that reinforces good habits because every task must get completed before the project can proceed.
Although some deadlines and milestones can be unpredictable during the testing phase, teams do have more structures with which to work. That means it tends to be easier to root out the issues that could be holding a project back.
8. The phases of the waterfall model are predictable and don’t overlap.
The waterfall model stays the same for every team in any industry. You go from requirement gathering and analysis to system design. Then you move to implementation before going to the testing step. At that stage, you will proceed to the deployment of the system. The final step is always the maintenance phase. Because each step gets processed and completed on its own, the phases will never overlap when using this approach to complete a project.
That means the requirements remain clearly defined at each phase. There is a complete understanding throughout the team about the expectations involved.
List of the Disadvantages of the Waterfall Model
1. The waterfall model doesn’t support making changes.
The waterfall model follows a set of steps that always keep a team moving forward. When you use the traditional methodology of this approach, then there is almost no room for change if something unexpected occurs during a project. A team can loyally follow each step until almost the end of the project but then encounter an unplanned obstacle. If a change in the goals or the scope of the work is necessary, then it can be virtually impossible to make the necessary pivot to keep moving forward.
2. It can invalidate the work you’ve previously accomplished.
When you need to make a pivot after completing some or most of a project, then the waterfall model isn’t going to let you proceed. The only way to get around this disadvantage is to find a way to complete the work at the current step where the difficulties occurred. If that outcome isn’t possible, then you’re stuck going back to the beginning of the process to start over with the new information.
That means a project that is unpredictable or involves frequent change needs room in each step for revision or reflection to avoid invalidating the previous work. If you use the traditional methodology, your team might find that it wasted a lot of time and energy.
3. This method excludes end-users and clients.
The waterfall model focuses on the internal processes of the work instead of looking at the client or end-user who gets involved with the project. Its main purpose is to create efficiencies within the internal systems so that internal teams can efficiently move through the different phases of a project. That means there isn’t much room available for someone to share ideas or opinions because the outlines become part of the planning stages.
That makes this method useful for projects that are known to have clear and unchanging goals from the beginning. If your team isn’t responsible for updating clients or end-users throughout development, then the waterfall model can work well. If you do have that responsibility, then a more agile methodology is likely needed.
4. It delays testing until after the completion of the project.
The waterfall model saves the testing phase of each project until the final half of the work is necessary. The traditional method makes it the fourth step out of six. Since the project is likely taken a considerable amount of time to complete at this stage, any adverse results could trigger the need for a significant revision. Ignoring the empirical data from the proposed value proposition until you start thinking about reaching the marketplace can result in significant user issues to manage.
This disadvantage is the specific reason why agile methodologies got developed. There is a lot of room for problems to remain unnoticed until you begin to reach the completion stages of the project.
5. The waterfall model can promote longer delivery times.
Because every phase requires a 100% completion of all tasks and documentation before transitioning to the next step, projects can take a lot longer to deliver when using this methodology. This disadvantage is the reason why complex assignments tend to avoid using the waterfall model. If an unexpected roadblock occurs, some teams might find themselves back at the starting point once again, creating an even more significant time deficit to manage.
6. It typically works better for small projects.
The waterfall model doesn’t work well for significant projects because it struggles to manage size and scope well. It’s like looking at the outline for a chapter in a book that an author follows in comparison to what an entire novel requires for composition. Although you could follow the larger structure successfully, the time and labor costs would be massive. You’d need to guarantee the completion of each stage before moving to the next one.
Smaller projects have fewer administrative needs, making it easier for leaders to track the progress made by their teams. It might ignore mid-process users and discourage client feedback with its rigid structures, but you can at least make specification changes when a project isn’t oversized.
7. Working models aren’t available until the latter stages of a project.
The reason why engineers and construction specialists love to use the waterfall model is that their work isn’t reaching completion until the latter stages of a project. It’s difficult to test the structural soundness of a building when you only have two walls built for it, after all. That’s why software designers prefer to avoid this approach. There can be testing needs that must happen along the way where a working prototype can be useful. This methodology doesn’t allow for that outcome to occur until late during the lifecycle.
The waterfall model remains a relevant choice today because of its straightforward and streamlined approach to development. It may not be suitable for every task or industry, but it also sets the stage to ensure completed work transfers to each step instead of relying on impartial results.
When you have small teams to manage with consistently predictable projects to complete, then this methodology provides a significant number of benefits to consider. If your teams are larger or the work is unpredictable, then another approach might produce better results for you.
If you’re looking at the waterfall model advantages and disadvantages today, then don’t be afraid to consider options that can customize this approach. When you can build in some flexibility into each step, then this methodology becomes a lot easier to manage.
Blog Post Author Credentials
Louise Gaille is the author of this post. She received her B.A. in Economics from the University of Washington. In addition to being a seasoned writer, Louise has almost a decade of experience in Banking and Finance. If you have any suggestions on how to make this post better, then go here to contact our team.