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SDLC: What Is The Waterfall Model?

Enrique Corrales
Published: June 10, 2022

What is Project Management?

Many software developers use the waterfall methodology to manage their projects. We will discuss what the waterfall software development methodology is, its different phases, and more so you can see how it could help your team meet its goals.

Read: Top 5 Project Management Certifications

What Is The Waterfall Methodology?

The waterfall methodology, or model, is a linear approach to project management that requires each phase to be completed before moving on to the next. It is so named since it is a sequential software development process that flows in a downward motion like a waterfall, with each project phase cascading into the next. The waterfall method starts with gathering customer and stakeholder requests at the outset of the project so a sequential project plan can be created to adhere to those requirements.

Waterfall is structured, thorough, and has been used for several years because it produces results for organizations in industries like software development, IT, and construction. For instance, software engineering projects are often managed using the waterfall software development life cycle (SDLC).

Most of the work in the waterfall method is done on the front end, especially as it pertains to research. This is because the method’s success depends heavily on the front end due to its linear nature. Unlike the Agile methodology that lets teams easily adapt on the go as obstacles arise, changing course is much harder with the waterfall method. Everything must be documented in advance, including user stories, interface, features, etc., so accurate time estimates can be produced and a predictable release date can be achieved.

Read: Best Project Management Tools for Developers

What are the Waterfall Methodology Phases?

The waterfall method works in a chronological manner that relies on fixed requirements, dates, and outcomes. Since it takes the linear approach, waterfall does not require individual execution teams to collaborate constantly. They are often self-contained unless specific integrations are needed. Team members following the waterfall method typically work independently. Unlike the Agile method, they do not have to provide frequent status reports.

Waterfall has five standard phases or stages, which may vary in name depending on where you look. We list the phases below as initially described by waterfall’s founder, Winston W. Royce. One phase cannot begin until the previous one is completed.

Requirements

A project cannot succeed using the waterfall methodology without collecting and fully understanding customer and stakeholder requirements in the first phase. Once those requirements are gathered, the subsequent phases in the overall sequence can be planned accurately. To ensure accuracy, all written requirements are often detailed in a single document that describes each project phase to include things like:

  • Assumptions
  • Dependencies
  • Risks
  • Costs
  • Timelines
  • Success metrics

After the first phase is complete, correspondence with customers will not resume (in theory) until the product is finished.

Design

Waterfall’s design phase is where software developers come up with a technical solution to the challenges presented by the product requirements. This solution can include layouts, scenarios, data models, etc.

The process of crafting a solution is divided into a pair of subphases. The first is the logical design subphase, where solutions are thought up and theorized, and the project’s scope, general traffic flow, and integration points are discussed. The second is the physical design subphase, where those ideas get converted into actual specifications via the team’s hardware and software technologies of choice.

Implementation

In the implementation phase, programmers use the requirements and specs from the previous phase to develop code. Implementation is usually the shortest waterfall phase since all of the research and design should be finished at this point. However, the team may have to revert to the design phase if significant changes are necessary during implementation.

Verification

The completed product is released to the customer during the verification phase once it has been tested for errors. The customer will review the product to see that it meets the requirements set out at the start of the project.

Maintenance

The customer continues to use the product in the maintenance phase to discover errors, bugs, and underwhelming features. The team makes any necessary fixes and releases updated software versions to ensure complete customer satisfaction.

Read: Project Management Software for Developers

What are the Pros And Cons Of The Waterfall Methodology

The straightforward nature of the waterfall model has kept it around for the long haul across multiple industries. Who is it ideal for? PMs who are tasked with projects that:

  • Have a clear vision of how everything will progress from the start.
  • Do not have vague requirements.
  • Have predictable customers who do not seem as if they will shift the project scope after it begins.

While a project manager who wants to know all design, time, and cost requirements upfront will likely prefer the waterfall method, it does have its downsides and is not for everyone.

First, let us discuss the pros of the waterfall model.

Waterfall Method Pros

  • All requirements are known from the beginning.
  • Each team member knows their specific role, what must be accomplished, and when.
  • With all of the necessary data and requirements upfront, estimating timelines, resources, and project costs is much easier and more accurate.
  • Progress is easier to measure against clearly defined milestones since waterfall employs such a structured approach.
  • Production delays are rare since customers do not have constant input into the process after the first phase is complete, which keeps change requests at bay.
  • The detailed information in the comprehensive requirements document allows new developers to join the project with minimal onboarding or adjustments.
  • The analysis and design stages allow devs to catch errors early on, so they do not make coding mistakes during the implementation phase.

Waterfall Method Cons

While the waterfall method is ideal for most software development teams and those taking on upfront, straightforward projects, it does have its drawbacks, such as:

  • Waterfall’s linear nature lacks the flexibility to adapt to unexpected obstacles.
  • Delivering projects via the waterfall method can take longer than the agile method since it takes a slower, chronological approach.
  • Some customers may not be able to detail all of their needs in the requirements phase, and some may not like the fact that they are not involved throughout the process, especially in the design and implementation phases.
  • If a customer is unhappy with the product they receive in the verification phase, reverting to the design phase can cost a lot of time and money.
  • A delay in one phase of the process delays the rest, causing deadline creep where the finish date keeps moving back a lot later than anticipated.

If the lack of flexibility that waterfall presents is too much to overcome, you may want to consider the agile methodology. It is a lightweight and iterative process that some software developers prefer since it uses short sprints (usually two weeks long or less) and customer feedback sessions to fine-tune a product on the fly. The customer continues to receive updates of the software in stages.

And, as they offer their feedback and developers tweak the software, it keeps improving until it becomes a finished, polished product that suits the customer’s needs.

Read more project management and software development lifecycle methodology tutorials.

Source: www.developer.com