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University of California, Davis

Application Development Methodology

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Rapid Application Development (RAD)

RAD Within a Planned Architecture

Danger of Rapid Development: The Nature of the Danger

Rapid application development is becoming increasingly essential to business survival. There is, however, a danger inherent in rapid development. Enterprises are often tempted to use RAD techniques to build stand-alone systems to solve a particular business problem in isolation. Such systems, if they meet user needs, then become institutionalized. If an enterprise builds many such isolated systems to solve particular problems, the result is a large, undisciplined mass of applications that do not work together.

In practice, most business applications are closely related to other applications and share databases with them, making a common infrastructure essential. In addition, as computing systems grow, they become ever more complex, and such systems are difficult to change unless they have been created within a skillfully designed architecture that allows one piece to be changed without changing the other pieces.

Problem with Not Having an Overall Business Systems Architecture

Most corporations did not until recently design overall Business Systems Architectures. As a result, as the installed base of applications has grown, flexibility has decreased. The consequent cost of maintenance has grown, often to 70 or 80 percent of the total IT budget. The task of replacing systems created in the absence of an overall architecture has now become overwhelming.

As the Number of Applications Grows, Flexibility Decreases

As the installed base of applications grows and becomes more complex, the flexibility of business systems decreases. Because such systems are difficult to change, they inhibit the ability of the enterprise to react quickly to changing business conditions. This has been a frequent source of frustration to CEOs and business strategists. Furthermore, as systems become more complex and less flexible, IT productivity decreases, because the constant effort to modify existing systems becomes a task of growing difficulty.

To combat these problems, RAD techniques must be used within an infrastructure designed for rapid evolution of integrated systems.