Change analysis: a step towards meeting the challenge of changing requirements

Changing requirements are a major source of risk to software development projects, but are generally not included in hazard identification and risk assessment procedures at present because the information needed is not collected or recorded by current requirements methods. It is proposed that change analysis should be an integral part of the entire development process so that change can be handled in a better-informed way with the associated risks being made apparent. Sensitivity analysis is proposed as the principal means of predicting two categories of hazard: which requirements are unstable and which design areas are most susceptible to changes in requirements. Impact analysis supports the decision-making process concerning the implementation of changes, and is also used to predict the impact of potential change for the assessment of risk. The paper considers what information is needed to enable sensitivity and impact analysis to provide an effective means of change analysis and what methods provide such information, emphasising the importance of traceability and the capture of design rationale. Because the potential for change would be made apparent early in the lifecycle the outcome should be a substantial contribution towards the goal of minimising the adverse impact of changing requirements on the project objectives