How is Agile Methodology Different than Waterfall?

One of the important dilemmas many developers face for their project implementation is “which development methodology to use?” Agile or Waterfall? There are several ways to develop a software, the definition of development methodology is the way of organizing the work of software development. It is not about the style of project management or a particular technical approach. While you will often come across these terms.

The two basic, most prominent development methodologies are Waterfall and Agile.

  • Waterfall: This methodology is more properly called as the “traditional” approach for software development.
  • Agile: It is newer than the Waterfall, a particular type of Rapid Application Development.

Both of these are mature, usable development methodologies involved in software development projects for a long time.

What is Waterfall Methodology?

Waterfall Methodology follows a linear, sequential process and is the most popular version of the system development life cycle (SDLC) for IT projects. Waterfall projects go through a number of overlapping or sequential phases.

It is planned using Gantt charts, which is a type of bar chart that illustrates the start and end dates of each task. This means that, once the eight stages – conception, initiation, analysis, design, construction, testing, implementation and maintenance are completed, a developer moves on to the next step.

In this process, once a step has been completed, a developer cannot go back to a previous step without starting the whole process from the beginning. Waterfall Methodology does not have any room for changes or error. An extensive plan must be set in the beginning and then follow carefully.

The Waterfall model originated in the construction and manufacturing industries. It is a linear approach to software development, the sequence of events are like:

  • Gather Required Documents.
  • Design.
  • Code and Unit Test
  • Perform System Testing
  • Perform User Acceptance Testing
  • Fix Any Issues
  • Deliver the finished product

Stages of Waterfall

There are eight stages in Waterfall method and are sequential. A developer cannot bounce back to analysis stage if he/she is in the testing phase.

Conception: This phase starts with an idea. The concept stage involves a rough calculation of the project, why it’s beneficial, and looks at any initial cost estimates.

Initiation: Once the idea is formed; define objectives, scope, purpose, and deliverables to a developer.

Requirement Gathering and Analysis: Requirements are gathered and analyzed to see if the project is actually feasible. All information should be documented.

Design: The design specifications created in this phase are used in the coding phase to actually write the code.

Coding or Implementation: The actual coding of the software begins in this phase. Any flowcharts or algorithms created in the design phase are translated into a programming language.

Testing: The software needs to be tested for any errors after the code is complete. When the testing is finished and found no errors or issues, the software is delivered to the customer.

Maintenance: Once customers start using the software in the real world, they may find additional issues. The development team will need to change, modify or resolve the software to continue to be active and effective.

Advantages of Waterfall Methodology

Waterfall method is best used for simple and unchanged projects. The linear and rigid nature of this method makes it easy to use and also allows in-depth documentation.

The advantages of Waterfall include:

Easy To Use and Manage: Waterfall method follows the same sequential pattern for each project, it makes easy for developers to use and understand. The developer does not necessarily need any prior training before working on a Waterfall project. It is also rigid in nature; each stage has particular deliverables and reviews, thus makes it easy to manage and control.

Discipline: Every stage in Waterfall method of software development has a start and end point. It is easy to share progress with customers. A developer can reduce the risk of the missed deadline by focusing on requirements and design before writing code.

A Well Documented Approach: Waterfall method requires documentation for every single stage, which provides better considerate of logic behind the codes and tests. A developer also gets a paper trail for further projects or a customer needs some more details about a particular development stage.

Disadvantages of Waterfall

As above explained, there is no room for changes or errors in Waterfall. The Waterfall method is sequential, linear, rigid model – you cannot bounce back or between the stages, even if an unexpected change or an issue occurs.

Here are few disadvantages of Waterfall:

Changes can’t be easily accommodated: Once the developer completes a stage of development, it cannot go back. If the developer reach the testing phase and an issue or error occur or a feature was missing, it is very difficult to go back and fix it. However, the developer has to go back to the initial stage and work on it again.

Software Is Not Delivered Until Late: Waterfall method is sequential, the project has to complete few initial stages before the actual code begins. Meaning, the customer will not be able to see the working software until late in the cycle.

Gathering Accurate requirements: The first stage of Waterfall project is to identify the customer’s requirement and gather accurate information. This could be challenging when a customer does not know what he/she actually want and instead, learn and identify requirements as the project goes on.

What Is The Agile Methodology?

Agile software development is based on an iterative, team-based approach to development. Instead of in-depth planning at the beginning of the project, Agile methodology is open to changes. This development method approach emphasizes the rapid delivery of an application in complete functional components. Rather than creating tasks and schedules in the Waterfall method.

Leadership encourages the teamwork in Agile methodology. Customer and developers must work together to align the software as per the company requirements and goals. However, the lack of initial design and steps, the Agile method is often criticized for its collaborative nature, which focuses on principals rather than process.

Principles of Agile Methodology

The Agile Manifesto lists out 12 principles to guide developer team.

  1. The highest priority is to satisfy the customer through the continuous and early delivery of software.
  2. Welcome changing requirements at any stage of development.
  3. Frequently delivering working software.
  4. Teamwork – developers and business people must work together throughout the project.
  5. Build projects around motivated individuals.
  6. Face-to-face conversation to conveying information with a team.
  7. Working software is the primary measure of progress.
  8. Agile processes promote sustainable development.
  9. Good design enhances agility.
  10. Simplicity
  11. The best design, requirements, architectures emerge from self-organizing developer team.
  12. Work on the product at regular interval to make it more effective.

Agile Development Cycle

Agile is flexible and always evolving. Here are the steps in the development cycle.

Planning: Planning is important in any development methodology, so do in Agile method. Once an idea is considered workable, the developer team works together to identify features. The goal of this stage is to break down the idea into a part (features), then to prioritize each feature.

Requirements and Analysis: The team needs to gather information through meetings with customer and users to identify requirements. These requirements must be detailed, relevant and quantifiable.

Design: The software design is prepared from the details of the previous step. The developer team should also come up with a strategy to proceed with the project.

Coding or Implementation: The actual coding of the software begins in this phase. Any flowcharts or algorithms created in the design phase are translated into a programming language.

Testing: The software needs to be tested for any errors after the code is complete. When the testing is finished and found no errors or issues, the software is delivered to the customer. During this phase, unit testing, integration testing, system testing, and acceptance testing are done.

Deployment: After testing, the product is delivered to customers for them to use. Once customers have been using the software in the real world, they may find additional issues. The development team will need to change, modify or resolve the software to continue to be active and effective.

Advantages of Agile

Agile focuses on flexibility, speed, and continuous improvement, rather than being linear, rigid nature as Waterfall methodology.

Here are few advantages of Agile:

Changes are Welcomed: With the Agile methodology, it is easy for a developer to accommodate and accept changes at any stage of the project. There is always an opportunity to prioritize, refine the backlog, and make changes to the project.

Undefined End-Goal: The Agile method is very beneficial for software development where the end-goal is unknown or not clearly defined. The goals come to light as the project progresses and development can easily adapt to these requirements.

Faster Delivery: This method allows developers to focus on high-quality development, testing, and collaboration. Conducting the test during each stage will help a developer to identify bugs and solve them faster. At the end, the high-quality product can be delivered faster.

Customers are Heard: Customers have many opportunities to see the project progresses and share their inputs, and see the impact on the end product.

Continuous Improvement: The Agile methodology encourages feedback from customers and developer team throughout the whole project. These feedback helps to provide continuous improvements to the project.

Disadvantages of Agile

Agile method’s flexibility nature is usually positive for developers, but it comes with few disadvantages. It can be difficult to initiate the project without a documentation, and undefined delivery date.

Without a documentation, the project can be neglected or the final product can be different than the intended original concept.

Here are some of the disadvantages of Agile:

Less Planning: Agile is completely based on time-boxed delivery and can prioritize tasks accordingly. This could possible sometimes scheduled for delivery may not be complete in time.

Requires Knowledgeable Team: Agile teams are usually in small size, so the developer team members must be highly skilled in their many concepts. The team also must feel comfortable and understand the Agile methodology.

Time Commitment from Developers: Agile is most successful methodology when the development team is completely dedicated to the project. Active collaboration and involvement are required throughout the process, which is more time consuming than a traditional Waterfall approach.

Conclusion

Waterfall and Agile methodology are very different in nature, and also difficult to choose between them both. The Waterfall can be used for almost any type of IT project. While the Agile method requires specific conditions and is not applicable to certain projects. Most of the conditions required for Agile is related to the working environment and practices that may or may not be employed by the whole project team.

By – Natasha Manuel

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