Evolving beyond requirements creep: a risk-based evolutionary prototyping model

Evolutionary prototyping focuses on gathering a correct and consistent set of requirements. The process lends particular strength to building quality software by means of the ongoing clarification of existing requirements and the discovery of previously missing or unknown requirements. Traditionally, the iterative reexamination of a systems requirements has not been the panacea that practitioners sought, due to the predisposition for requirements creep and the difficulty in managing it. The paper proposes the combination of evolutionary prototyping and an aggressive risk mitigation strategy. Together, these techniques support successful requirements discovery and clarification, and they guard against the negative effects of requirements creep. We embody these techniques in a comprehensive software development model, which we call the EPRAM (Evolutionary Prototyping with Risk Analysis and Mitigation) model. The model was intentionally designed to comply with the Level 2 Key Process Area of the Software Engineering Institute's Capability Maturity Model. Validation is currently underway on several software development efforts that employ the model to support the rapid development of electronic commerce applications.