The waterfall model has become a permanent feature of project management in many companies, not only in the IT industry. It is the most popular and used method of project management. It won’t come as a surprise when you understand the simplicity and effectiveness of this system.
What is the Waterfall model?
The waterfall model is the first published model of the software development process. It consists of successive phases. The phases take place one after the other and each of them is individually tested to verify their usability. If there is a need to modify the rebuild, it can be done in a given fragment and in a dedicated team, without the need to involve people who are not responsible for the given part. Make as many iterations as needed to achieve your goal.
This model is very popular even outside the IT industry. You can indicate its use in construction, production, or other industries where we deal with repetitive design work.
In the cascade model, the stages of the software development process follow one another in a strictly defined order:
- Requirements definition and analysis. The goals of the system, its services and limitations are agreed during meetings with the users of the system. They are defined in detail and then serve as a system specification.
- System and software design. The system design process divides the requirements into hardware and software systems. Establishes the overall architecture of the system. Software design involves identifying and describing the essential abstractions of a software system and the relationships between them.
- Implementation and testing of units. In this step, the software design is implemented as a collection of programs or program units. Unit testing is about checking that each unit meets its specification.
- System integration and testing. Program units or programs are integrated and tested as complete systems to ensure that the requirements are met. After testing is complete, the system is delivered to the customer.
- Operation and maintenance. This is usually the longest phase of the life cycle. The system is installed and handed over to the practical user. Maintenance includes fixing errors that were not found earlier in the life cycle, tweaking system unit implementations, and enriching system services as new requirements are discovered.
Each subsequent phase only begins after the (often formal) completion of the preceding phase.
The general model contains phases that must be completed one after the other. First, the concept phase, which is very important. Thanks to a well-prepared plan, we can avoid later corrections or, in the worst case, starting from scratch.
Once the theoretical framework is established, work begins on the application itself. They include analysis, design and construction, in that exact order. Then comes the testing phase that will help you verify and spot unwanted errors. Implementation of the application takes place after the project in the production phase is completed. After the premiere, it’s time to handle the finished product.
History of the Waterfall model
The genesis of the waterfall model goes back to the middle of the previous century. Its name was suggested by Winston W. Royce in 1970 in an article “Managing the Development of Large Software Systems”. The creator himself had doubts about this method and guessed its unreliability. He called it “risky and troublemaker.” However, it quickly proved its advantages in the field of programming.
The Waterfall model is valued above all for a detailed plan that creates sequences of task execution. It is their effect that is to be the final solution. It is assumed that the time frames, i.e. deadlines, are strictly adhered to. In addition to all performed activities, documentation is also prepared.
As a general rule, tasks are carried out sequentially, without exceptions. It is about completing individual tasks in the allotted time so as to control costs and not affect the success of the entire undertaking.
Some limitations are a downside. If there is a need to make a modification or change, you must go back. Lack of flexibility as you cannot proceed without completing the previous phase.
However, if the tasks are performed as planned, each participant will quickly notice that the model will work in many environments due to its clarity and ease of use.
Disadvantages of the Waterfall model
The imposed order of tasks may hinder the course of the project, or even extend it, due to the fact that you cannot proceed to the next stage without completing the current one.
In a situation where the client has some suggestions or wants to introduce previously unforeseen changes, the team is forced to start work from scratch or rebuild a given stage. This situation is certainly complicating, as the work cannot be resumed. In addition to extending the duration of the project, the costs also increase. However, if you get things right, a skilled development team shouldn’t have any problems.
The testing phase is also a problem for this type of project. They can only be carried out after the project has been completed. Although it introduces some order to the work on the application, it can mean additional work time, because errors are not caught on a regular basis. Writing the code in the dark will certainly generate more defects, which the testers will then have to catch and fix in the last phase.
The biggest disadvantage of the cascade model is its inflexible division into disjoint stages. Commitments must be made very early in the process. This means that it is difficult to react to the changes that occur. If the client does not specify his measurements in the first phase of the project, it may turn out that his later changes and requirements will not be implemented. Therefore, it is recommended to use this model when the requirements are clear and understandable.
Advantages of the cascade model
Of course, the cascade model has its advantages which, under certain conditions, speak in favor of it. If you want to use this method, you need to plan your work and the entire project well. Very detailed descriptions count. All technical details regarding the most complex elements will be helpful in further development work.
In this method, it is important to know the purpose, use of the application and, above all, the client’s needs. During planning, detailed documentation is created, which will be used in further work by everyone involved in the project. This will definitely help in its implementation.
Concrete planning and creating a clear project framework means client confidence in the result of the work.
If the plan is reliably implemented, the initial concept should completely coincide with the finished product.
A predetermined schedule and project valuation will prevent costly deviations from assumptions. The investor will get a predefined application that meets the agreed requirements.
The Waterfall model is free from misunderstandings. Thanks to a strict plan and documentation, a certain rhythm of work is set. It has no breaks to arrange details. The team is guaranteed a certain comfort of work and the awareness that the requirements addressed to them are predetermined. There are no surprises here.
Thanks to the documentation, you can smoothly pass parts of the project to a subcontractor or introduce a new specialist, without the need to change the date of completion of works.
It can be said that Waterfall is not a perfect model, but thanks to its strict assumptions, it will be a perfect solution for many development projects. A predetermined formula, however, does not have to be rigid, and above all, it does not exclude creative input.
It is a model that serves the client, employees and the project itself. An experienced team will appreciate this way of working because it generates less stressful situations and allows you to work smoothly and without disruptions.
If a cascade model fits your scope of work, don’t think twice!