What is the Waterfall methodology in project management?

Popularly known as the Waterfall model, the Waterfall methodology is a well-established sequential, linear process of managing projects. It maps out a project into precise sequential phases, with every phase wrapping up completely before the next one begins. The process flows like a waterfall through the different stages of a project.

Waterfall methodology is one of the most traditional techniques in project management. It is very straightforward, with people working linearly toward achieving a common end goal. Each team member plays a specific role, and no changes are expected in any goals or phases.

Agile and Waterfall methodologies are two popular approaches to project management. The primary difference between the two is that Waterfall involves a linear process that requires team members to finish each phase before proceeding to the next, and Agile methodology allows team members to handle different project phases simultaneously. Agile was developed as an alternative to Waterfall's rigid framework, enabling team members to introduce changes to the project even very late in the process.

The Waterfall methodology is used in various project management contexts, including product development, IT, manufacturing, construction, and software engineering.

It is used by project managers whose project meets the following requirements:

• The concept of the project is clear. The Waterfall model is ideal when the team perfectly understands the entire concept.

• The project is low risk. The model is best for projects with minimal risk. For example, if you are confident the team can successfully deliver the product without returning to previous phases, or if the project does not involve a lot of customer engagement, use the Waterfall methodology.

• The project is stable. The Waterfall methodology works best for projects that require minimal changes.

• The requirements are clear. This methodology works well when the project's requirements are clear. Any ambiguity will disrupt the process flow, making it hard to achieve the set goals.

• The project is short and not costly. A simple, pocket-friendly project is easy to manage using the Waterfall methodology.

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Here are some top advantages of using the Waterfall model in project management:

• A clear structure. The Waterfall methodology follows a rigid structure. This sequential model comprises different phases, each having distinct goals and deliverables. This makes it easy for team members to work through each stage to deliver the desired results.

• Easy transfer of information. Because each stage of the Waterfall model has specific deliverables, it is easy to pass information about the project from one phase to the next. This facilitates a seamless knowledge transfer between group members, allowing new teams to carry on with the project when needed.

• Stability. Given that the Waterfall model follows a linear approach with requirements and deliverables defined upfront, the project has a sense of structured predictability.

• Early setting of goals. The first phase of the Waterfall model involves goal-setting, which helps group members understand their objectives before the project starts. This ensures the team understands their roles and how they will handle the project.

Just like all other models, the Waterfall methodology has its weaknesses. The drawbacks to Waterfall include:

• Inflexibility. Its lack of revision opportunities means it’s almost impossible to make changes mid-development. Also, changing the scope during the project's life cycle can bring the project to an end or require nearly starting over.

• Planning overhead. All requirements must be set and communicated before development, adding to planning overhead.

• Doesn’t suit complex projects. It is not the best to use for high-risk or complex projects.

• Doesn’t suit long projects. Given its inflexible nature, it is not ideal for long, ongoing projects.

• Client doesn’t see iterations. The client only sees the final product after completion.

The stages of the Waterfall methodology differ from project to project. Generally, the phases of the Waterfall model can be divided into six stages:

1. Requirement-gathering and documentation

2. System design

3. Implementation

4. Testing

5. Delivery

6. Maintenance

1. Requirement-gathering and documentation

This is the first stage of the Waterfall model, where the project sponsors provide the project requirements. Often, one or more group members will meet the client to gather the requirements and understand how they would like the system to work.

The ideology of the Waterfall methodology is that all customer requirements are collected at the start of the project, allowing for planning out of consecutive phases without customer involvement until the project's completion.

2. System design

This second stage, popularly known as the analysis phase, involves reviewing the collected requirements to establish a design to meet them. Common things considered in this phase include:

• Data inputs and outputs

• Process mapping

• Visual design

• Overall specifications

The design phase also covers the project's objectives, budget, and schedule. Consider this phase the blueprint for the complete project.

3. Implementation

This phase executes the project's plan and design to produce the intended product. The project team integrates the requirements from Phase One and the design from Phase Two to generate an actual product.

4. Testing

In this phase, the development team hands the project to the quality assurance team for testing to verify that the product developed in the previous phase meets the project's requirements. Smaller issues that get identified are fixed. Larger issues may require revisiting the requirements.

5. Delivery/deployment

Once the fully functional product is complete, it is made available to end users and clients. Training and documentation may also be produced as part of the official delivery. This is often the phase when the project is considered final.

6. Maintenance

If the client discovers any system bugs, errors, or faulty features that occurred during production, the development team fixes these issues until the customer is satisfied. Maintenance extends beyond the six phases of project management well into the product's lifetime.

Here are some examples of industries that can benefit from the transparency and precision of the Waterfall model:

• Manufacturing companies. Manufacturing teams use the Waterfall management model for maximum efficiency when running various manufacturing and production processes. For example, an electronic gadgets manufacturer must wait for assemblers to complete their task before they can begin packaging.

• Construction companies. The Waterfall model is ideal for the construction industry because it makes completing specific tasks easier. For instance, the painting team cannot begin their work until the walls have been built and plastered.

• Software development. Waterfall methodology can work well in software development because it facilitates the organization of the various workstreams. The model is used in large-scale software development projects where a structured approach is required to ensure projects are completed on time and within the set budget.

• Government projects. The Waterfall methodology is used in most government and defense projects that require a rigid and structured approach to meet all requirements within a stipulated time.

• Healthcare projects. Healthcare, especially pharmaceuticals, can significantly benefit from the Waterfall model. By nature, scientific practice is orderly, with clearly defined end products. For instance, when developing a new drug, scientists first establish a hypothesis and follow a strict set of steps. Every time they fail, they go back to the drawing board with an adjusted hypothesis.

The Waterfall methodology is best suited for projects with well-defined requirements that are not likely to change drastically during development. It works well for projects with several steps to production that require a lot of predictability.

Most construction and manufacturing industries have long used the Waterfall model. This methodology also works well for healthcare and government projects.

The Waterfall model is best for small projects with clear goals that are well understood, where there is no room for change in the requirements.

Google, the tech giant, combines Waterfall and Agile Scrum. That said, Google attributes most of its success to Agile Scrum because the methodology allows continuous improvement, cross-functional teams, and flexibility in incorporating change.

Waterfall is a common project management model. Scrum is a method used to implement an Agile approach. It is fluid and iterative, breaking down large projects into small, manageable tasks completed in short “sprints.” It allows teams to handle different phases of a project simultaneously. The Waterfall model takes a more traditional route to project management with sequential phases that require the team to complete each stage before proceeding to the next.