Agile-Scrum and the Waterfall Model

Abstract

The purpose of this paper is to define the Agile/Scrum model and the Waterfall model. The paper will also define specific differences between the two models. The type of projects that are best suited for each method will also be discussed in this paper. Lastly this paper will discuss how the Agile/Scrum methodology would either benefit or not, project development within an organization.

Waterfall Model

The waterfall model was the first software development life cycle approach used for software development. It is one of the easiest models to follow as you must complete one phase before you can move onto the next. There is no overlapping of phases, which is why the waterfall model is also known as a linear sequential life-cycle model. The outcome of one phase is then used as input into the next phase. There are a total of six phases within the waterfall model: requirements, design, development, testing, implementation, and maintenance. Progress is seen in a steady downward flow where one phase cascades seamlessly into the next, hence the name waterfall model.

While each software development is different, and may require different suitable software development life cycle approach models, the waterfall model is best suited for specific situations:

• Requirements are very well documented, clear and fixed.
• Product definition is stable.
• Technology is understood and is not dynamic.
• There are no ambiguous requirements.
• Ample resources with required expertise are available to support the product.
• The project is short

Waterfall Pros and Cons

One of the major advantages of the Waterfall model is that it allows for departmentalization and control. The waterfall model is extremely user friendly, simple, and easy to use. Individual deadlines can be set for each phase allowing for a specific schedule and timeline to be set. However a major disadvantage of the waterfall model is that it does not allow for much reflection or revision. Once you move from one phase to the next it is difficult to back to the previous phase to make revisions or changes when issues are found. Therefore no working software is developed until the later phases.

Agile Model

        The Agile  model takes into consideration different iterative and incremental process models and focuses primarily on process adaptability and customer satisfaction as it rapidly delivers software. The “agile model believes that every project needs to be handled differently and the existing methods need to be tailored to best suit the project requirements (SDLC-Agile Model, n.d., para. 4).”  The agile model takes the product and breaks it into small incremental builds that are provided in iterations. A single iteration can last anywhere from one to three weeks. Unlike the waterfall model where one phase must be completed before moving onto the next, the agile model has different teams that simultaneously work within different areas such as planning, requirements analysis, design, coding, acceptance testing, and unit testing.

Agile Pros and Cons

        The agile model is a realistic approach to software development and promotes teamwork as well as cross training. The agile model is best suited for environments that change steadily and delivers early partial working solutions. Again unlike the waterfall model the agile model requires little to no planning. However, some of the cons include higher risk of sustainability, maintainability, and extensibility. The agile model does rely heavily on customer interactions, therefore if a customer is not clear the team may be driven towards the wrong direction.