Waterfall methodology is a widely used project management method with a linear approach. In Waterfall, each stage of the workflow needs to be completed before moving on to the next step. While there are various types of project management methodologies, Waterfall is well suited for projects where the objectives are clearly outlined from the beginning. This article covers how Waterfall works, what projects the methodology is best suited for and how it compares with Agile, another project management method.
The Waterfall approach was established in 1970 by Winston w. Royce. It contains five phases of management, where each requires a deliverable from the previous phase to proceed. Waterfall is ideal for projects like software development, where the end result is clearly established before starting, and is best suited for projects that require a lot of predictability.
There are five phases of the Waterfall methodology: Requirements, Design, Implementation, Verification and Maintenance. Below, we discuss each phase and the purpose for each one.
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Stages of the waterfall method
The waterfall method has an inherently methodical nature that leads a project through straightforward steps. There are typically five to seven phases in this method. Though the specific names and number of steps can vary depending on the developer or project, the concepts usually remain the same. Here are the basic phases of the waterfall model:
The customer requirements for the end product are gathered at the beginning of the project and compiled into a requirements document to guide the process. These requirements generally list what the application should do without considering how it will be accomplished. By gathering the requirements at the start of the project, it eliminates the need for further customer involvement and allows the team to plan every other phase.
This is the stage when you review the requirements and develop a design to meet them. Once the requirements have been gathered, the system is then evaluated to gauge the tools needed and to create the models that will be used in the finished application. Here, your team identifies the path it will take to deliver a solution and the relevant specifications.
The design phase can be broken up into two subphases: logical design and physical design. During the logical design subphase, solutions are brainstormed to meet the desired requirements. It is during the physical design subphase that the theoretical ideas are transformed into concrete plans and design specifications, such as services, data layers and programming languages.
It is during this phase that the actual code is written to meet the specifications, models and requirements that were outlined in the previous phases. Some testing may take place, and if significant changes are required during this stage, this may mean going back to the design phase.
Once the code has been written, beta testers, quality assurance and any other relevant testers explore the application systematically to discover any issues or defects within the software. This phase, also known as the verification phase, usually necessitates a repeat of the coding phase to address any bugs that are found. Occasionally this phase also involves the customer, allowing them to test the product to ensure that all requirements have been appropriately met.
After testing has been completed, the application is ready to be released. This final phase often consists of ongoing support by keeping the application current and functional, as well as addressing any bugs or errors when they are found.
What is the waterfall method?
Even though its popularity has diminished over the years in favor of increasingly more agile methodologies, the waterfall models logical nature and simple implementation maintain its prevalence in the industry. When using this method, customer and stakeholder requirements are collected at the start of the project and then used to develop a sequential plan to accommodate them. Though most commonly used in software development, the waterfall method can also be used in various other IT projects as well as in construction.
Waterfall vs. agile
The two main distinctions between waterfall and agile methods are customer involvement and linear action. When using the waterfall method, each phase has to be completed before the next phase can be started. In an agile model, the functions of testing and development occur simultaneously. Additionally, the agile methodology encourages communication between testers, managers, developers and customers throughout the development process, whereas the waterfall method collects customer requirements at the beginning of the project and then limits their involvement from thereon.
When utilizing an agile methodology, the project is planned in “sprints” rather than milestones. Tasks are prioritized and completed in short periods, often in two-week intervals. Rather than outlining the phases during the requirements stage, all tasks are flexible within this model and are completed based on different variables, such as customer feedback and the success of preceding sprints.
Advantages of the waterfall model
Though its prevalence has waned over the years, waterfall methods can still provide many benefits to a projects development process. This is especially true for larger organizations or projects that need stringent deadlines and stages to guide them. Here are a few of the other advantages of using the waterfall model:
Limitations of the waterfall model
Though there are many benefits to using the waterfall method, changes in development and technology have proven the agile method to be more advantageous in most situations. Here are a few of the challenges you may face when using the waterfall model:
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- Collecting and documenting stakeholder requirements.