Project management always involves a specific methodology and best practices. It’s worth knowing both the modern ones and the classic ones, like waterfall.
Waterfall, or cascade model, is a linear approach in which customer requirements are gathered at the very beginning and then a coherent plan is created to implement those requirements. The cascade approach was first described by Winston W. Royce in 1970 and was quickly adopted across industries because of its logical consistency and ease of implementation. Today, this model is being displaced by modern and more flexible approaches such as Agile and Scrum.
Due to the rigidity of the model, project development is fast and the cost and deadline are predetermined. Unfortunately, this approach will give an excellent result only in projects with clear and predetermined requirements and ways to achieve them. There is no backtracking and testing is done almost after all work is completed. The cost of implementing any changes is high because you have to wait until the entire project is complete to initiate it. The general principles of the waterfall model can be stated as follows:
1. Documents and instructions are important, everything must be written.
2. The next stage of work does not start until the previous one is completed.
3. No stage can be skipped.
4. If product requirements have changed after agreement – the customer must report this formally and the task list is revised.
5. You cannot go back to a previous stage to change something.
6. No iteration – there is one common process for product development.
7. Identifying and correcting errors – only at the testing stage.
8. The customer is not involved in the product development after the list of tasks and requirements has been established.
The model proposed by Royce is extremely simple and understandable. According to him, work on a project should proceed in several consecutive stages, from the first to the last. Their number may vary depending on the project and the scheme – we will discuss the five-stage version:
Requirements gathering and assessment. Simply put, at this stage all the base documentation is created, according to which the work on the project will be carried out. First of all, the customer’s requirements and wishes are analyzed and then projected onto the company’s capabilities and the state of the market. The result of the analysis is a document describing what the final product should do, but not how and with what tools.
Design. At this stage the logic of product operation is established. Still no concrete implementation decisions are made, but the functioning of all product elements is described. At the end, you can already estimate how much time and personnel the project may require.
Constructing. Here we are already talking about concrete tools for the tasks. The appearance of the finished product is also developed for the first time. This stage accounts for most of the work on the project.
Testing. Quality control, beta and all other testers detect and report problems of the product. If there are a lot of bugs, it causes a return to the design stage.
Handover. The finished product can be presented to the customer and handed over. Since this stage also includes maintenance and support, interaction with the previous phases is inevitable.
In recent years, waterfall has surrendered its leadership to more flexible methodologies. However, the cascade model is still relevant for large projects and organizations and has several advantages:
The waterfall model was relevant in the 1970s, but now, half a century later, more and more companies are moving away from it in favor of younger and more modern solutions. The main disadvantages of the cascade approach that discourage contractors are:
It turns out that the cascade methodology is an excellent solution in terms of time and reporting, but it is very poor in terms of quality. That’s why today it’s only recommended for three cases:
Although these 3 points are becoming less common in practice, the cascade model will continue to be popular and in demand for a long time because of its transparent organization.
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