Rapid Application Development Agile Testing

The RAD first appeared in the 1980s,when James Martin developed the approach in response to increasing dissatisfaction with the failure of earlier methods such as the waterfall model of software development. These earlier approaches were characterized by being highly prescriptive, with developers following an inflexible series of development phases in which requirements were gathered early in the process and then set in stone throughout the rest of the project. Typically, customer involvement was limited to the initial requirements capture and final acceptance testing, resulting in an unacceptably high number of delivered systems that did not match the actual customer needs (which had almost certainly changed since they had been first documented anyway). Cost and time overruns were the norm for such projects and,since much of the testing was left to the later phases, the systems were frequently delivered with major quality issues.Initially inspired by the work of other prominent workers in the field of development and testing,such as Barry Boehm, Brian Gallagher,and Scott Schults,and following a gestation period of several years, Martin’s thoughts on rapid software development were finally formalized as RAD Rapid ApplicationDevelopment .

The key goals of RAD are

  • high-quality systems,
  • fast development and delivery,and
  • low costs.

RAD seeks to break down the approach taken in monolithic waterfall projects into smaller iterative steps, increasing the opportunities for the customer to be involved in the development and to be exposed to earlier prototypes and working increments of the developing system. In fact, the development of software prototypes is a key aspect of RAD, providing a means of exploring the customer needs for the system through informal testing and managing customer expectations of how the final delivered system should look and perform.

RAD proved to be of benefit over traditional development approaches in a number of areas:

  • RAD’s iterative approach to developing software meant that testing could beginearlier in the development process and could continue more frequently throughout the project. This approach significantly reduced the risk of late identification of serious defects and the associated cost overruns and late delivery frequently seen in waterfall projects.
  • Closer customer involvement in the development process, with early opportunities to test how well the software met customer needs using the prototypes, meant there were less show-stopping surprises when the system was finally delivered.
  • Accepting that requirements would no longer be set in stoneat the very beginning of the project and that changes could be managed effectively throughout the development using requirements planning workshops and joint application design workshops, helped ensure the delivered software would more closely match customer expectations.
  • Tighter project management of development priorities, costs and timescales through the use of techniques such as time boxing kept project progress on track and controlled the extent that the development could get out of control.

On the down side,for many practitioners who followed more traditional software development models,RAD gained the reputation of being an excuse for “hacking” or “opportunistic coding,” as it has also been called. It is possible that,as one of the earliest agile methods, RAD may have been perceived as having less rigor than the more established approaches. Also, RAD’s focus on developing a series of rapid prototypes, many of which inevitably would not be carried forward into the final deliverable, was often blamed for wasting time and effort and jeopardizing progress. Finally, the process of prototyping was often poorly implemented due to a weak understanding of what prototyping actually involved, leading to a poor perception of the technique.

Despite some suspicion from the defenders of the more traditional development methods, RAD arguably set the scene for the development of a number of the later agile methods.

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