A requirements change impact analysis should be performed when

Requirements change impact analysis is performed before a change is approved, while the change control board is reviewing the request. The purpose is to evaluate how the proposed change will affect requirements, design, code, test cases, schedule, cost, risk, documentation, baselines, and related configuration items. If impact analysis is delayed until after CCB approval, the board may approve a change without understanding its consequences. Placing items under control and marking them as baselined are configuration management activities, but they do not by themselves trigger impact evaluation. Software quality engineering requires objective analysis before change decisions are made so that approvals are based on risk, feasibility, traceability, and total lifecycle impact.

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