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Blog post 20 May 2022

Waterfall Methodology

Waterfall Methodology

The Waterfall methodology is one of the most popular, oldest and most traditional methodologies in project management. This type of methodology is followed in a project where requirements are well known and fixed and no further changes are expected.

waterfall methodology illustration

What is the Waterfall Methodology?

The waterfall methodology is a linear sequential design process, originating in software development processes. The Waterfall model was developed by Winston Royce and presented in 1970. The waterfall development method originates in the manufacturing and construction industries; highly regimented physical environments that are very difficult or impossible to change or adapt once work has begun.

In the early days of software development, there was no concept of Agile methodology or iterative life cycle. In fact, until the late 1990s, the majority of software projects followed a simple “waterfall” type life cycle: gathering all the requirements upfront; designing the solution; building it; testing it; releasing it to users for acceptance testing (UAT); fixing any bugs; and then releasing it into production.

This Waterfall approach worked well for many IT projects because they tended to be tightly scoped in both time and cost, with relatively fixed requirements that did not change much during the course of the project. Projects were small enough that changes could easily be managed by simply adding an extra week or two at either end of the project timeline without causing any real problems.

6 Common Stages in a Waterfall Project Management

The Waterfall Methodology is not exactly a method as much as it is an approach, however, the six distinct stages that make up this cycle are very common in most software development processes.

waterfall project management model

The number of stages involved can vary depending on the project but these six stages are the most common among all projects using the Waterfall methodology. Following is an overview of each stage of the Waterfall project management process and what each one entails:

1)   Requirements

The first phase of the Waterfall model is to gather all the requirements for the project, which are usually outlined by the client. The team will conduct interviews, research and review existing documentation to determine what needs to be done. This phase is often called "the discovery phase."

To understand what a business organisation needs, you must first listen to its stakeholders and collect as much information as possible. Make sure you are not rushing into planning or design without a clear understanding of your client's business goals, target users, and any potential obstacles that may arise later in the process.

2)   Design

In the second phase, the project begins with a design process that outlines the end result and how it will be achieved. This is typically a very detailed plan and is highly unlikely to change throughout the project since there are no opportunities for re-work later on in the process. Once this step is complete, it moves to implementation.

3)   System Testing

At this next phase, all system components are tested. This includes integration test, which makes sure that each part works properly with the others; functional test, which guarantees that all functionality meets requirements; and test of performance, which ensures that the system can handle peak loads without crashing or slowing down significantly.

4)   Implementation

During the implementation phase, each element of design is put into place one at a time, with each team member completing their assigned tasks in sequence before passing on their work to the next individual or group in line. There is not a lot of overlap or communication between teams during these phases—each team stays focused on their own piece of the puzzle until they finish and pass it on (hence the waterfall name).

5)   Verification/Integration

Once every element has been completed according to plan, these pieces are put together through integration and verification testing processes that ensure all elements fit together seamlessly as intended at each phase of development by validating that each feature works properly and meets its requirements before moving forward to create more features — even if those additional features do not work properly yet when combined with others that have already been developed because they are not ready to be tested yet as part of integration verification.

6)   Maintenance

After the project is completed, any bugs that are found are squashed, and customers get to actually use the finished product. Maintenance also applies to adding new features or functionality. This phase may come after the product has been completed and used by customers, and it could potentially end as soon as you are happy with the finished product.

Advantages and Disadvantages of the Waterfall Methodology

Although the Waterfall methodology is one of the most stringent and planned out project management approaches, it is not without its set of advantages and disadvantages.

waterfall model advantages and disadvantages

Advantages

Presence of a clear structure. The waterfall methodology follows a distinct structure. It is a sequential model which consists of different phases, each phase having its own set of goals and deliverables. The initial phase consists of the analysis of the project requirements. This is followed by designing, testing, implementation, verification and the maintenance phase. The requirements are determined in the early stages and remain constant throughout the development life cycle. The final result is delivered in the last phase i.e., the maintenance phase.

Smooth transfer of information. Since each phase of Waterfall project management approach has a specific deliverable, information about the project can easily be passed from one phase to another, allowing for a smooth transfer of knowledge between team members. As this knowledge is often presented through documentation, this allows other teams (e.g., maintenance or support) to easily pick up where previous ones left off should the need arise.

Easy to manage. As mentioned above, the Waterfall methodology has a clear structure with well-defined goals and deliverables for each phase of the project life cycle. Thus it is easy to manage this type of project as every milestone has to be achieved before going to the next level. Due to this, it becomes easier to track the progress of work and identify any kind of bottlenecks or delays that might have occurred during any phase.

Early determination of goals. The initial phase of the Waterfall model involves a lot of planning, research and brainstorming, which helps you determine your goals and objectives before diving into the actual work. This allows your team to have a clear idea of what they are trying to achieve as well as how they are going to go about achieving it.

Extremely stable. The Waterfall methodology follows a linear approach which means it is extremely stable in nature. There are no chances of deviation from the original plan once the system requirements have been finalised. This makes it easier for managers to predict any potential problems during execution.

Disadvantages

Costly and inflexible. The Waterfall model is a linear sequential design process, meaning that you have to complete one phase before moving on to the next phase. This process is highly structured and regimented in a way that does not allow for much flexibility.

All phases of the project need to be completed before you can move on to testing. As a result, if your client decides to add or modify something late in the process, it may require going back through all previous phases — which could be costly.

Does not prioritise the client or end-user. Unlike other software development models, the Waterfall project management approach does not prioritise feedback from customers when developing a product. Instead, it focuses on meeting requirements that were determined earlier in the project lifecycle. The problem with this approach is that requirements can change — especially as users start using your product and providing valuable feedback.

Delayed testing. The Waterfall methodology does not allow for testing until it reaches the final stage of the development process, which is known as system testing. However, it can create an issue because by then, many resources would have been applied to each preceding stage. So if testers find any issues at this stage, business owners can incur losses caused by rework.

No scope for revision or reflection. When you are working with a project that is made up of many parts, it is important to be able to make revisions and reflect on what has been accomplished so far. Since you are not able to go back and make revisions until you get to the end of each phase, this approach may not always work out well if you need to shift in a different direction than planned before the completion of each stage.

Waterfall vs Agile Methodology: What's the Difference?

If you have got a big, sprawling project that involves lots of moving parts and stakeholders, you are probably working on a waterfall methodology. The idea is to have a plan and then move forward at the same time.

difference between waterfall and agile methodology

If your team members are used to working in an iterative, agile environment, they are going to have trouble adjusting to a more top-down approach. But that does not mean they cannot work together effectively. In fact, the most successful agile teams are those that work together well and effectively throughout the entire process.

Agile Project Management is about rapid testing, frequent delivery, and continuous refinement. That is great for projects that require constant updates — like selling software or taking down a website when something goes wrong — but it is not so good for projects that need to be built from scratch.

waterfall model

For this reason, agile methodology is focused on short-term projects that deliver value quickly, while long-term projects remain stuck in the planning and implementation phase. Agile development emphasises collaboration and communication throughout the project lifecycle, as well as using iterative planning — changing plans during implementation so that all parties are working toward a common goal.

If you are interested in learning more about Agile, the Institute offers a Certified Agile Project Management course. This course is focused on explaining different Agile modules that way broadening your knowledge of Agile project management, which upon completion of the course, is testified by IPMA Agile certification.

Waterfall Project Management is focused on long-term projects and tends to rely on a more approach of hierarchy, documentation and bureaucracy. This process is more commonly used for software development, but it can be applied to any product development process.

In addition, it involves putting everything into place before any code is written. If you're building a website, for example, you'll want to decide on the look and feel of your site before you start coding anything at all. Then you'll create wireframes and mockups as an early step in creating the actual site. From there, you can build the pieces of your site one by one until it's done.

What is the Waterfall Methodology Used For?

The waterfall methodology has proven to be an effective approach for a variety of endeavours, including:

  • Software development. Software projects can be complex and take years to complete. The Waterfall methodology breaks each project into manageable tasks, allowing the development team to focus on one aspect at a time before moving on to the next.
  • Systems engineering. When engineers create systems that include multiple components, they must ensure that all parts fit together seamlessly from start to finish. Each component is worked on individually using the Waterfall model, ensuring every element fulfills its purpose when integrated with others.
  • Project management. From construction projects to marketing campaigns, the Waterfall process can help the project management team coordinate tasks so each phase is completed in a timely manner before moving on to the next step.
  • Manufacturing. Following an assembly line method and creating each product part by part are essentially applying the Waterfall project management approach in manufacturing environments
  • Process engineering. Due to their strict sequencing of activities, many factory production processes require engineers use this model when designing them from scratch or making changes according to new regulations or quality requirements.