Rapid Application Development (RAD) is also known as Rapid Application Building (RAB). Software that is driven by user interface requirements is ideal to be developed using the RAD methodology. It was developed in the 1970s and 1980s. RAD mainly focuses on an adaptive process and puts less emphasis on planning.
What is Rapid Application Development?
RAD is a prototyping technique employing various tools and techniques to produce software using minimal code quickly.
JAMES MARTIN RAD Model
James Martin’s RAD model has the following 4 phases:
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Requirement Planning Phase
System planning and system analysis phases of the Software Development Life Cycle (SDLC) have to be combined in the requirement planning phase of the RAD model. Managers, IT staff members, and users agree on the business requirements, project scope, available constraints, and system requirements.
The last step of this phase is that the team agrees on the key issues and obtains the authorization of management to continue.
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User Design Phase
In this phase, the user communicates with the system analysts and develops models and prototypes to represent all system processes, inputs, and outputs. Next, the RAD team uses a typical combination of the Joint Application Development (JAD) technique and CASE tools to convert the needs of a user into working models.
This phase allows the user to understand, modify, and eventually approve the working model that meets their requirements. Therefore, this is a continuous working process.
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Construction Phase
This phase is similar to SDLC, which focuses on program and application development tasks. The difference is that, in RAD, however, the user can continue to participate in changes and modifications. The user can still suggest improvements as actual screens or reports are developed. The task included in this phase is programming , application development, coding , unit integration, and system testing .
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Cutover Phase
This phase resembles the final tasks in the SDLC implementation phase. It includes the task of data conversion, testing, the changeover to the new system, and user training.
If we compare this with the traditional approach, in the RAD model, the whole process is compact. In the end, a new system is built, delivered, and placed in operation much sooner than before.
Advantages and Disadvantages of the RAD Model
The following are the remarkable benefits and drawbacks of RAD:
Advantages
- Changes in the requirements can be accommodated at any time.
- RAD increases the reusability of components.
- It focuses on customer needs and encourages their feedback.
- RAD reduces the project development time.
- The RAD model gives higher productivity with fewer people in a short time.
- Progress is easy to measure in each phase of the RAD model.
- A working product is ready very quickly.
- It uses powerful tools to shorten the iteration time.
- Initial reviews are quicker than others.
- It becomes possible to divide a project into small and easily achievable parts.
- This provides integration from the very beginning of the process, and that solves a lot of integration issues.
Disadvantages
- RAD can be performed only on those systems that can be modularized.
- It requires highly skilled developers and designers.
- Management is an important part of RAD. Therefore, management complexity is also more than in other software development models.
- User involvement is a must-have throughout the life cycle.
- Technically strong or skilled team members are necessary for identifying the business requirements of the user.
- RAD highly depends on modeling skills.
- The cost of modeling and automated code generation is very high. Therefore, RAD is impractical for projects with budget constraints.
- The RAD model suits systems that are scalable and component-based.
RAD Model vs SDLC Approach
In SDLC, a high emphasis is on requirement analysis and information gathering before the project starts. That’s why the user gets pressurized and doesn’t get the feel of their product as there is no working and building for a long time. Maybe customers need to change something after they get to see the software.
So the traditional approach is a rigid process, and it is not feasible to do major changes to the project once it gets complete.
The RAD model, on the other hand, is an ongoing process with continuous user involvement that speeds up the delivery of the project. Fast delivery and continuous user involvement decrease the risk of non-conformity with the actual user requirements.
RAD is very efficient in getting the required project with rapid delivery. This is due to the reusability of components and parallel development. RAD will result better if skilled engineers are available to work on the projects. There are higher chances for the customers to get on-time delivery of the project.
When to Use the RAD Model ?
It is possible to apply the rapid application development model only in some particular conditions. The RAD model can be successfully applied if it is possible to break a project into modules. Modularization is the most important task to perform in the RAD model to reduce the time of project work.
RAD is ideal in the following scenarios:
- Budget is the main factor that determines the application of the RAD model. If the budget is sufficient to apply the automated code-generating tool, then we can use RAD.
- When skilled developers and domain experts are available with relevant business knowledge.
- Modeling is an important phase of this model. Therefore, the availability of designers decides the applicability of RAD.
- This can be used if the requirements change during the project, and this is to be presented to the user in small iterations of 2-3 months.
Alternatives to Rapid Application Development
There are lots of different methods for developing software, but there are mainly two methods that are suitable alternatives to the rapid application development model:
1) Waterfall Model
The only difference between the SDLC RAD model and the Waterfall model is the structured environment of the latter. So when you want to work with a large corporation, Waterfall might be a good choice for getting the project done smoothly.
Although RAD was created in response to the inadequacy of the Waterfall model, whenever a user is focused on the structured way of designing, it's suitable to follow the waterfall methodology. While the Waterfall model is not the preferred choice of modern developers, you may go with this if you are working in a very structured environment.
2) Lean Development
Lean development methodologies are the solution if you think RAD is expensive to afford for your project development. This reduces the waste throughout the project. This can be made possible by scrapping unwanted or unneeded features in the development.
The Lean model allows using a part of RAD and other methods when implementing it. The main focus of lean development is to work on a thin budget rather than creating a high-quality project.
Conclusion
That was all about the rapid application development model, a.k.a. RAD. It is a fast software development model that is the most suitable when you don't have budget constraints, and highly skilled developers and designers are available.
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