What is RAD (Rapid Application Development Model)?

 First proposed by IBM in the 1980s, the Rapid Application Development model is one of the more popular SDLC models. Also known as the RAD model, the software development model emphasizes speed and flexibility over thorough initial planning.

The RAD model has a very short development time span. Generally projects developed with the RAD Model have a delivery time of 60 to 90 days.

One of the most important highlights of the Rapid Application Development model is support for powerful development tools, such as C++, Java, Visual Basic, and XML, and the techniques they incorporate.

What is RAD?

Rapid Application Development (RAD) is a development model that prioritizes rapid prototyping and rapid feedback over extended development and test cycles. With rapid application development, developers can create multiple iterations and software updates quickly without needing to start a development schedule from scratch every time.

Rapid Application Development (RAD) was created in the 1980s, so it's definitely not something new. But unlike the waterfall model, it is not singular. This is the evolution of a philosophy of sustainable development according to the needs of a given time.

What are RAD Models?

Any software development project that can be divided into smaller modules, which can be assigned independently to different teams can be developed using the RAD Model. All of these various modules are ultimately combined to get the final product.

The development of each module of a software development project using the RAD model follows some of the basic steps of the waterfall model. This includes analyzing, designing, coding, testing, implementation, and maintenance.

The Rapid Application Development model prioritizes rapid prototyping and rapid feedback of extended development and test cycles.

RAD developers are allowed to make multiple iterations and updates to the project under development without starting the development schedule from scratch each time.

RAD started when software developers began to realize that the traditional waterfall model was not very effective. The waterfall model is unable to accommodate software development projects with evolving requirements.

The main drawback of the waterfall model is that once the software development process reaches the testing phase, it is nearly impossible to change the core functionality and features offered by the software being developed.

Although the RAD model appeared in the 1980s, it has continued to evolve since then. This is in stark contrast to the waterfall model, which is the same as it is today at its emergence.

RAD Model Stages

The RAD Modeling process involves building a prototype and then sending it to the customer for feedback. This feedback is then taken and changes made to the prototype before sending it back to the customer.

This process repeats until validation is performed by the customer. After that, the SRS document was developed and the design finalized. The final product is then built around this final design.

There are 4 distinct phases of the Rapid Application Development model. These are requirements planning, user description, construction, and cutover. Each is explained as follows:

1. Requirements Planning

This is the first phase of the Rapid Application Development model. This involves procuring the requirements of the software project under development. This is what differentiates the RAD model from other software development models.

Unlike other software development models, the first phase of the RAD model asks for broad requirements. The broad nature of these requirements makes it possible to assign specific requirements to projects during various points of the development cycle.

For requirements elicitation, a variety of techniques are used, including brainstorming, Facilitated Application Development Technique (FAST), form analysis, task analysis, and user scenarios.

The Requirements Planning phase also includes a complete structured plan. This explains:

* Important data

* Methods to get important data

* Critical data processing procedures to form the final model

2. User Description (User Description/User Design)

The second phase of the Rapid Application Development model is the user description. This involves taking user feedback and then building multiple prototypes of the project under development using developer tools.

Instead of working with a strict set of requirements, RAD developers create a number of prototypes with different features and functions. All of these prototypes are then reviewed by the client to decide what to discard.

The user description phase includes reviewing and validating the data collected during the first phase. This phase also includes identification and explanation of dataset attributes.

3. Construction

The construction phase includes the refinement of the prototype developed in the previous stage. It also includes the use of powerful automated tools to transform process and data models into final operational products.

All of the improvements and modifications collected were implemented during this third phase of the RAD Model. Feedback on what was good, what was bad, what to keep and what to delete is given in this phase.

The feedback provided during the construction phase is not limited to functionality, but also includes aesthetics, interfaces, etc. Prototypes are then proceeded with all the feedback received considered.

Prototyping and feedback continues until the final product according to the client's requirements is developed in the most suitable way.

4. Cutovers

The last phase includes the finalization of aesthetics, features, functions, interfaces, and everything related to the software project. Interfaces between various independent modules require proper testing. This is done in the cutover phase.

To do the above, powerful automated tools are used. This is followed by customer acceptance testing. Ensuring the desired level of maintainability, stability and usability of the developed software is mandatory before delivering the final product to the client.

RAD Vs Other Software Development Models

The Rapid Application Development model is very different when compared to other software development models. The RAD model focuses on speed, while most of the other software development models emphasize delivering a working product to the customer.

Compared to other software development methodologies, RAD teams consist of fewer members. Hence, communication becomes clear and fast. Since the RAD Model aims for speed, development time is less when compared to other Models.

Most software development models have user input only at the beginning and at the end of the development cycle. However, the RAD model keeps the client engaged throughout the entire software development process.

RAD advantages

* Since fewer developers are needed, the cost of the whole project is much less

* Customer feedback is available during the early stages

* Due to the shorter iteration timeframe, it is easier to accommodate frequent changes in requirements

* Easy to measure development and progress of software projects through various phases

* Total software project time under development is significantly reduced due to the use of reusable components

* Use of powerful development tools ensures better product quality

Disadvantages of RADs

* The absence of reusable components increases the probability of project failure

* Customer engagement is mandatory during the entire lifecycle

* More complex to manage when compared to other software development models

* Projects that are not capable of modularization cannot be developed using this software development model

* The cost of using powerful automated tools and techniques may exceed the project budget for smaller projects. Therefore, the software development model is not suitable for small-scale projects

* Team leaders need to work closely with developers as well as customers to meet deadlines

* Using effective and powerful tools is required for highly skilled professionals

Conclusion

So what is RAD? Rapid application development (RAD) is a methodology that focuses on rapidly developing applications through frequent iterations and continuous feedback.

The Rapid Application Development model is one of the best software development models available today. Due to its constantly evolving nature, it is able to survive for a long time.

Like other SDLC models, the RAD model has its own advantages and disadvantages. Outlining all the requirements of a software development project allows choosing the best SDLC approach. However, that's where the RAD model really shines.

You don't need to be completely sure of all your requirements when starting with the RAD Model. The software development methodology helps in identifying requirements alongside the software development process.

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Resa Risyan

Just an ordinary person who wants to share a little knowledge, hopefully the knowledge I provide can be useful for all of us. Keep in mind! Useful knowledge is an investment in the afterlife.