Cascade life cycle model: advantages and disadvantages

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Software development is not like traditional engineering. A methodology is what is used by developers to break down work into manageable progressive steps where each can be reviewed to ensure quality. Teams work together with the customer to create a finished software product using one of the software development methodologies. The most popular of them are the spiral, waterfall, or cascade model (Waterfall); RAD, or Rapid Application Development; Agile Model, or flexible and iterative, or iterative model. There are other options, but in this article we will consider only the waterfall, or waterfall, project life cycle model, and also explore its advantages and disadvantages. Let us immediately explain that it is a sequence of certain steps, and its peculiarity is that the new stagenot possible until the previous one has been completed.

The history of the waterfall model

Methodology in its traditional form leaves little room for unexpected changes. If the development team is not too large, and the projects are predictable, then Waterfall can ensure that they are completed on time.

The waterfall development model has been around for over forty years. It was first described in a 1970 article by W. Royce as one of the very first official models for the development process. It was described as ineffective for large software development projects, but no one forbade its use for small ones. Nearly half a century after it was discovered, this technique is still relevant in today's business world. It has been called the obsolete model and is treated with some disdain due to the obsolescence of the traditional project management approach. But Waterfall is a useful and predictable approach if the requirements are fixed, well-documented and clear, if the technology is understandable, and when the project does not take much time to complete. In this case, the software life cycle waterfall model can provide a more predictable end result for a given budget, time frame, and scope of work.

What is the waterfall development model?

The Waterfall model can be described as a linear, sequential development of a project, where processes constantly move from requirements to design, then to implementation, verification and deployment withsubsequent ongoing maintenance. It is believed that the cascade life cycle model was created thanks to W. Royce, although he himself used an iterative development model.

The main emphasis in Waterfall development is on planning, timing, goals, budgets and ultimately the implementation of the entire system as a single entity. The main benefits here are simple forward and backward planning and implementation.

Description of the waterfall model

Compared to other methodologies, Waterfall focuses more than others on a clear, defined set of steps. The original model consisted of five stages. It is often described as a linear sequential life cycle model. This means that it follows a simple phase structure, where the results of each phase progress to the next level of development. The main steps are:

1. Collect requirements and create documentation.
2. Design and system engineering.
3. Implementation.
4. Testing and deployment.
5. Support.

Teams must complete the entire step before moving on to the next one, so if something isn't ready by a certain deadline, it becomes immediately noticeable. Also, unlike Six Sigma or Scrum, Waterfall does not require certification or special training for project managers or employees.

Criticism of the waterfall model

Cascade model of information system life cyclehas been criticized for its inflexibility after completion of each step, and for delaying the client's ability to provide feedback. However, this methodology can work well for smaller projects with limited budgets. It is often compared to one well-known project life cycle methodology, PRINCE2, which was created by the UK government. This methodology is still used in the public sector. One of the key differences between PRINCE2 and the Waterfall Life Cycle Model is that the latter requires a written description of all requirements from the outset, as they can be difficult to revise later. Before the creation of any code begins, they must be precisely defined and fixed. This is an important advantage of the waterfall life cycle model.

Pros and cons of the waterfall model

Because technical documentation is a necessary part of the initial requirements development phase, it means that all team members clearly understand the goals of the project. New developers can quickly understand the rules of code creation and join the workflow without any problems. When using a waterfall model of the life cycle of an information system or project, phased execution ensures discipline.

Each step has a well-defined starting point and conclusion, making it easy to track progress. This helps to reduce any deviation of project execution from agreed timelines.framework. In this model, in contrast to the spiral, the software is considered as a whole. Therefore, provided that all requirements are met, it works more efficiently. If we continue to compare the cascade and spiral life cycle models, we can conclude that the first is more universal and can be applied in various areas.

Requirements negotiation phase

Another advantage of the waterfall life cycle model is that costs can be estimated with a fairly high degree of accuracy once all requirements have been identified. If it is applied, it means that at the first stage all test scenarios are already described in detail in the functional specification, which makes the testing process simpler and more transparent. And even before the software development begins, the design is worked out in detail, which makes the needs and the result clear to everyone.

One of the great things about using Waterfall is to strive for the end product, or end result, from the very beginning. Therefore, teams must avoid deviating from the target. For smaller projects where the intent is fairly clear, this step makes the team aware of the overall goal from the start, reducing the chance of getting lost in the details as the project moves forward. Waterfall's approach is very methodical, which is why it emphasizes the importance of clean communication at every stage. In the software development process, new people appear at each new step. Therefore, it is important to strive toto document information throughout the project life cycle.

Disadvantages of the waterfall life cycle model

Potential development issues can be investigated and resolved during the design phase. Alternative solutions are also being worked out and the optimal ones are selected. All this happens before the start of the project. Many organizations appreciate the attention to documentation right from the start, as it also means that there should be no surprises with the final product. But in practice, it is rarely possible to do without making changes. It is often difficult for clients to understand their own needs in terms of functional specification only at the requirements stage. This means they can change their mind once they see the final product. Such a problem is difficult to solve. Sometimes an application has to be almost completely redesigned.

Lack of flexibility in the waterfall model

Another downside of the cascading IP (or project) life cycle model is the potential lack of flexibility. Questions may arise to accommodate new changes or changes in requirements that have occurred since the initial consultations.

Adjustments due to business plans or market influences may not have been taken into account in planning. Also, projects can take longer to complete compared to using an iterative methodology such as Agile.

Important points when using waterfall methodology

When it comes to developing Waterfall, it is very important that software developers can effectively guide and advise clients in order to work around all these problems later. Often the most critical aspect of applying the waterfall lifecycle model is that customers don't really know what they really want. In many cases, true two-way interaction between developers and clients does not occur until the client sees the model in action.

For comparison, in Agile development, the client can see fragments of the working code that were created during the work on the project. Unlike Scrum, which divides projects into separate sprints, Waterfall always focuses on the end goal. If your team has a specific goal with a clear end date, Waterfall eliminates the risk of missing a deadline when you're working on it. Based on these pros and cons, Waterfall development is generally recommended for projects that are not likely to change or need new development during the life of the project.