Scenario T3 - The impact of a change is assessed

Motivation

This scenario addresses the investigation of a change to the point at which its impact is understood and a response to the change can be developed.

Pre-conditions

Requirements exist at various levels and are traced. A change to a given requirement is proposed. This requirement is referred to as the 'root requirement'.

Scenario

1. An impact graph is assembled by following satisfaction relations from the root requirement to all other linked requirements.
   1. This graph becomes an independent resource, individually addressable, and separate from the underlying requirements structure
2. All requirements in the impact graph are reviewed for relevance to the change, and those that are not impacted by the change are removed from the graph ('pruned')
   1. Pruning a given requirement from the impact graph will also remove lower level 'branches' of the graph that are rooted in the pruned requirement
3. Requirements that are not present in the impact tree are reviewed for relevance to the change. Where any are considered to be impacted, they are added to the impact graph together with any associated relationships (the graph is 'enriched').

Post-conditions

An impact graph exists (a collection of linked requirements) as an independent resource that can be attached to another artefact (e.g. a change request or an issue).

Notes

This scenario can also be used to assess the impact of non-compliance upon higher level requirements.

-- SimonWills - 05 Feb 2010