Rapid Application Development (RAD) is a model that prioritizes rapid prototyping and quick feedback through long development and testing cycles. It allows developers to quickly create multiple iterations and software updates without having to start the build schedule from scratch each time.
The origins of the Rapid Application Development (RAD) concept date back to the 1970s, so it is definitely nothing new. It was then that the efforts to create business applications easier and faster began. Unlike the waterfall model, it is not singular. It is a continuous evolution of the development philosophy as required at a given time.
RAD is a development model that emerged after developers realized that the traditional cascade development model was not very effective.
Rapid Application Development methodology
Since its inception, RAD has undergone changes and various versions of it, but it includes four basic steps that still apply today to RAD models:
1. Outlining the requirements – the first phase where all members (managers, IT staff, users etc.) plan and determine all the needs, requirements, scope and challenges of the project. What distinguishes RAD from other models in this phase is that it has extensive requirements to maintain flexibility over time.
2. User input – The phase defines the collaboration between users and developers to create one or more prototypes meeting specific system requirements. This is a continuous phase where users interact with the prototype. They provide important feedback until the actual end product is approved.
3. Construction – this is the phase that works in tandem with the user’s contribution. This step focuses on implementing user-provided feedback through coding, testing, and other development tasks. The second and third phases work together until users approve the product.
4. Finalization – Once the product has been approved, it is time for the developers to make the last touches. For this purpose, they perform all the necessary tests and user training. Once the product has been positively assessed for stability and durability, it is ready for handover.
Rapid Application Development Lifecycle
RAD’s inspiration from the system development cycle (SDLC for short) can be seen. The four stages of the RAD can be viewed as a condensed version of the SDLC. We recall the following stages:
1. Planning: assessing factors such as project requirements, scope and feasibility.
2. Analysis: examining the situation and objectives of the project to determine what needs to be created.
3. Design: create a more detailed design outline (often with multiple flow diagrams) including details such as screen layout, program functions and rules.
4. Implementation : The product goes through various stages of development until it is ready for the end user.
5. Testing: The software is tested at various levels to ensure system readiness.
6. Assessment / Maintenance: After training and transition periods, the software is maintained and regularly assessed to assess any shortcomings or potential improvements.
RAD vs Agile
Rapid Application Development and Agile are terms used to describe an iterative software development process. Each of these approaches is designed to address issues to which traditional development methods – such as the cascade approach – are prone. Although the two terms are often used interchangeably, there are some differences.
Agile Software Development has grown in importance with the Agile Software Development Manifesto, a shortlist of the core principles and guiding values for Agile Development. In short, they are largely in line with RAD; an iterative design process, regular contact with customers / users and acceptance of changes in requirements are just a few common features.
However, the Rapid Development of Applications is slightly different from Agile development when it comes to the software itself. While regular user input is one of the key features in Agile, the process continues to focus on the robust architecture and design of the system. Basically, Agile development aims to achieve the same iterative flexibility as RAD, without sacrificing durability or technical excellence.
Advantages and disadvantages
Due to its flexibility and the ability to adapt to new inputs, the RAD method carries much less risk than the basic planned method. With early prototypes, it’s easy to identify key design challenges. Therefore, RAD eliminates any potential problems early in the life cycle, making it cheaper and easier to solve during the development process. Therefore, RAD designs are usually shorter.
Likewise, using and evaluating prototypes during the development process allows users to provide feedback and identify potential changes more effectively. Users can modify and customize the prototype to accommodate any feedback and observations, rather than planning the final result in advance (as with the basic cascade model). To some extent, this makes RAD a cyclical approach in which product evolution goes hand in hand with user experience.
Thanks to continuous feedback and the flow of interaction with users, projects developed in the RAD model can be more useful and easier to implement in a business environment. As the software changes from user to user, the end product is more likely to be appreciated by the end user and provides user-friendly features.
Finally, the RAD method can deal with any budget problems more easily. Due to its flexibility and incremental nature, the RAD approach allows developers to identify and solve financial and technical problems faster and to respond appropriately. Compared to the cascade method, the risk of large-scale failure is significantly reduced.
There are several key drawbacks to RAD approaches as there are trade-offs associated with user flexibility and functionality. First, an emphasis on user experience and feedback can ultimately reduce the importance of non-functional requirements (or NFRs) in the development process. Put simply, focusing on improving what the (functional) software does can overlook the system architecture (non-functional) and overall structure.
While the NFRs are not visible to the end user, they are important to the longevity of the software. In order to use the RAD approach properly, the design must also meet certain constraints. First, any design that cannot be modularized does not fit RAD; in a similar vein, large-scale projects simply require too much control and method planning.
In addition, RAD requires users to test the prototype throughout its life cycle. If the number of users or their feedback is insufficient or unhelpful, the project may come to a standstill. By sacrificing control for flexibility, RAD relies on a reliable and helpful user base to develop the product.
Rapid Application Development has become a major trend in the software development world. It is a relatively new approach that promises seamless and fast production of new applications to meet the ever-increasing development demands of companies from various industries.