The RAD model is proposed when requirements and solutions can be modularized as independent system or software components, each of which can be developed by different teams. After these smaller system components are developed, they are integrated to produce the larger software system solution. The modularization could be on a functional, technology or architectural basis, such as front-end-back-end, client side- server side and so on.
RAD becomes after if the software engineer uses component technology such that components are really available for reuse. Since the development is distributed into component development teams, the team work in tandem and total development is completed in a short period.
RAD is also recommended when system components have already been developed by the organization in the context of other software systems. And these components can be used in the new system with minor or no modification. The model is RAD due to the responsibility into smaller components and the possibility of splitting the requirement into smaller components that can then be assigned to different development teams.