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Which Methodology to Choose for Your Project: Waterfall vs RAD?

When companies are thinking of developing software they do thorough marketing research, analyse the end user needs, think how to further promote it to make their product or solution successful by all means.

However, they do not usually think of how the software will be built, who will be responsible for requirements preparation and project management and so on. It might cause serious delay in project release or even a project failure.

For instance, the Wellingtone survey states that only 40% of projects are developed on time, 46% of projects are developed according to the planned budget, and 36% of projects deliver their full value.

According to this data, most projects cannot be considered completely successful. (Source:

One of the most effective ways to decrease potential risks and costs is to choose the relevant software development methodology and follow it. However, there is no “silver bullet,” because each methodology has its characteristics and specifics.

In this article, we will analyze two popular software development methods – Waterfall and RAD (Rapid Application Development).

We will discuss their differences, as well as their strong and weak sides, and also explain in what situations it is better to choose this or that methodology.

What Is the Waterfall Software Development Methodology?

The Waterfall methodology may be considered a traditional linear software development model.

It consists of several phases sequentially following each other.

The software development model Waterfall is called so because the development  stages form a cascade, where each step gradually follows the previous one.

A developer can’t get to the next development phase until the previous stage is completed. Moreover, development can go only forward, so engineers can’t influence the already completed stages.

Here is how the development process based on the Waterfall model may look like. (Source:

When using the Waterfall model, developers take a linear and straightforward approach to software development. In this methodology, the development process usually consists of the following steps:

  • athering document requirements;
  • design creation;
  • implementation;
  • QA and testing;
  • bug fixing and release;
  • maintenance and support.

Now let’s look at the other model – RAD – Rapid Application Development.

What Is the RAD Software Development Methodology?

RAD (stands for Rapid Application Development) is one of the varieties of Agile development methodology that is based on iterations and rapid prototype development.

Unlike the Waterfall model, this methodology doesn’t imply strict adherence to the plan and requirements, but rather a verification of user reviews and rapid improvement of the software.

The main goal of this model is to create a product as quickly as possible and bring it to customers.

When applying the RAD approach, the client can see the approximate end results of the work in the early stages of the development.

The development process based on the RAD methodology looks like this. (Source:

Here are the main steps of the RAD-based development process:

  • defining project requirements;
  • building prototypes;
  • gathering user feedback;
  • testing;
  • presenting a system.

What Are the Main Differences Between Waterfall and RAD?

Given that both models are very different in their natures and structures, the decision between them can greatly affect the development process, the choice of a contractor, and so on.

Now let’s compare  Waterfall and RAD software development methodologies and see how they are used  in practice:

Development Time

Project development timeframes can vary greatly depending on a particular software development methodology.

The average time taken to develop a software product is 4.5 months. (Source:

When utilizing the Waterfall model, there may be a long waiting time for software implementation. The thing is that Waterfall involves many stages and some of them are quite lengthy in time.

For instance, planning is one of the longest stages of Waterfall development and developers must go through it before moving to the execution phase.

On the other hand, the goal of the RAD approach is to deliver a product as soon as possible. Moreover, developers who choose RAD may work faster because they more often tend to reuse the code or utilize automatic code generators. Sometimes, the customer may get the first versions of the product within the first two months of development.

Regarding the time of development, there are some more points that can affect the speed of  the project completion. First, companies need to understand that the completion of the project is perceived differently when using this or that development methodology.

A process based on  Waterfall implies a clear structure of the development process, well-defined deadlines, and a clear result.

An example of a software development plan. (Source:

In contrast to the Waterfall model, development projects based on the principles of RAD are open ended because they are are completed only when the client is satisfied with the result.

On the other hand, if the c