Advantages and Disadvantages of Waterfall and Agile Methodologies

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In the world of software development, two methodologies reign supreme…Waterfall and Agile. While these methodologies both aim to streamline project development, they take different approaches in doing so and typically have cult followings of Project Managers who prefer one over the other.

But what makes these methodologies so different? What are the benefits and limitations of each? In this article, we will explore the advantages and disadvantages of each process in such a way that you can decide which methodology you prefer or best suits your project.

Waterfall methodology is a sequential, linear approach to development from initiation to deployment. Because Waterfall processes are unidirectional, phases must be reviewed and signed off on at completion. This makes project development well-defined and easy to explain to stakeholders and developers.

Agile methodology is best described as a flexible, iterative approach to development. Agile projects most often use Scrums to break down the project into small chunks of time called Sprints. Agile processes focus on team involvement throughout the sprint and allow for changes to requirements at any point.

What is Waterfall?

The Waterfall method has long been the traditional approach to software development. This method breaks a project down into different phases that are completed sequentially with requirements review at the end of each phase. The different phases of a Waterfall cycle may vary with different organizations, but a typical cycle could look like this:

  1. Requirements gathering and documentation
  2. Design
  3. Development
  4. System testing
  5. User Acceptance Testing (UAT)
  6. Deployment

As the name implies, with pure Waterfall implementations, you cannot swim upstream to a previous phase. You must complete the full development lifecycle before returning to the top.

Let’s look at the advantages and disadvantages of the Waterfall method.

Waterfall Advantages:

  • Due to meticulous planning and requirements gathering upfront, the customer knows what to expect. They have an idea of the size, cost, and timeline for the project with a clearly defined idea of what the fully implemented system should do.
  • On projects where the customer is hands off, Waterfall is a great solution. Other than reviews, approvals, and status updates, customer involvement is not necessary once the requirement phase has been completed.
  • Progress can be easily measured because the full scope of the project has been defined in advance.

Waterfall Disadvantages:

  • The Waterfall method is only successful if each phase is fully completed before moving on to the next phase. Requirements gathering is the first and most crucial phase for any project. However, I have found this the most challenging aspect because customers can miss details, and details are critical with this approach. It can also be difficult for a customer to fully visualize the end result strictly from a requirements document. Prototypes and wireframes can help remedy this limitation but there can still be a disconnect between visuals and the written requirements.
  • Changes in the business needs or project requirements are not easily adapted due to this finite approach. Changes can be made, but not without significant adjustments in timeline and overall cost.
  • Finally, system and user acceptance testing only occur at the end of the project lifecycle. The impact of any bugs that are found could be substantial and difficult to correct and without extending the project timeline and budget. If an error in code is created early in the project, but only realized during testing, this could have affected how other code was written.

What is Agile?

Agile provides teams with the flexibility to respond to changes through incremental, iterative phases. Rather than plan everything upfront, this method focuses on lean development and producing minimum viable products (MVPs) during each time increment, called “sprints”. Each sprint has a definitive time, usually measured in weeks, to complete a list of deliverables and tasks planned at the start of a sprint. The business prioritizes the tasks that are kept in a backlog to keep track of the desired features and requirements.

Agile methodologies place an emphasis on collaboration, continual user feedback, incremental improvements, and the flexibility to adjust to requirements as they evolve.

Here are my thoughts on the advantages and disadvantages of the Scrum Agile methodology.

Agile Advantages:

  • Customers have the opportunity to review and change requirements after the initial planning stage and are expected to do so.
  • The customer sees results frequently and early in the project lifecycle due to the sprints. This gives a sense of instant gratification that some customers prefer.
  • Customers play a hands on role working directly with the project team and take on a sense of ownership.
    At the end of each sprint, customers have the opportunity to prioritize the backlog and reevaluate the remaining tasks. This flexibility allows the customer to keep the project in line with the company’s focus and goals which may have changed over the course of the project.
  • Bugs are identified and resolved during each sprint allowing for adjustments to be made before the end of the project.

Agile Disadvantages:

  • While customer involvement is required and encouraged, this can lead to additional requirements adding to the timeline and overall cost of the project. If a sprint is not completed in the designated timeframe, additional sprints may be added, again adding to the overall time and cost.
  • Some have the opinion that Agile projects are best managed when the team is centrally located. I feel that there are various ways of staying connected with remote employees on projects. A few of my favorites include video conferencing with GoToMeeting, team communication through Slack, and project management tools such as JIRA.

Which method is right for your project?

Waterfall is ideal for your project when:

  • The scope, budget and timeline are not flexible
  • Clients are more hands off
  • The size of the project is smaller and fairly simple
  • Quality and definition is more important than speed of development

Agile may be preferred when:

  • Flexibility of the project scope is needed
  • Client involvement is a priority
  • The project is complex and large scale
  • Rapid production outweighs quality

Both Waterfall and Agile are effective methodologies for successful project development and implementations. While Agile is gaining in popularity and adoption, Waterfall is still a tried and true approach to project management. The majority of our projects take on an Agile approach but only after the scope is reviewed and the client is fully educated on the process.

By Victoria Cloeren

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