Rapid Application Development (RAD) 

As the name suggests Rapid Application Development (RAD) model is an incremental software process model that focuses on short development cycle time. This model is a “high-speed” model which adapts many steps from waterfall model in which rapid development is achieved by using component based construction approach.

In case if project requirements are well understood and project scope is well known then RAD process enables a development team to create a fully functional system i.e. software product within a very short time period may be in days.

RAD model is like other process models maps into the common and major framework activities.

Phases of RAD Model

Communication is an activity which works to understand the business problem and the information characteristics that should be accommodate by the software.

In RAD model Planning is required because numerous software teams works in parallel on different system functions.

Modelling includes 3 major phases –

1.      Business modeling

2.      Data modeling

3.      Process modeling

Construction focuses mainly on the use of existing software components and the application of automatic code generation.

Deployment establishes a basis for subsequent iterations if necessary.

A business application which can be modularize in a way that allows each major function to be completed in less than three months is useful for RAD. Each major function can be addressed individually by a separate RAD and then integrated to form a whole application.

 Diagram of RAD Model 

Advantages of RAD Model

1.      Flexible and adaptable to changes.

2.      Prototyping applications gives users a tangible description from which to judge whether critical system requirements are being met by the system. Report output can be compared with existing reports. Data entry forms can be reviewed for completeness of all fields, navigation, data access (drop down lists, check-boxes, radio buttons, etc.).

3.      RAD generally incorporates short development cycles – users see the RAD product quickly.

4.      RAD involves user participation thereby increasing chances of early user community acceptance.

5.      RAD realizes an overall reduction in project risk.

6.      Pareto’s 80 – 20 Rule usually results in reducing the costs to create a custom system.

Disadvantages of RAD Model

1.      Unknown cost of product. As mentioned above, this problem can be alleviated by the customer agreeing to a limited amount of rework in the RAD process.

2.      It may be difficult for many important users to commit the time required for success of the RAD process.

Drawbacks of RAD Model

1.      RAD requires sufficient human resources to create the right number of RAD teams

2.      If developers and customers are not committed to the rapid, rapid-fire activities necessary to complete the system in a much abbreviated time frame, RAD projects will fail.

3.      For RAD system should be properly modularize otherwise it creates lots of problems to the RAD model.

4.      Rad approach does not work properly if high performance is a major issue, and performance is to be achieved through tuning the interface to system components.

5.      When technical risks are high RAD may not be a suitable option. This may be possible while an application heavy uses a new technology.

When to use RAD model:

§  RAD should be used when there is a need to create a system that can be modularized in 2-3 months of time.

§  It should be used if there’s high availability of designers for modeling and the budget is high enough to afford their cost along with the cost of automated code generating tools.

§  RAD SDLC model should be chosen only if resources with high business knowledge are available and there is a need to produce the system in a short span of time (2-3 months).