What is Requirements Traceability?
It is the ability to describe and track the life of a requirement from its conception, through the specification and development, down to its deployment. This activity needs to be performed both upstream and downstream.
Requirements Traceability allows us to identify the source of each requirement and track all changes affecting them. However, if we trace requirements not only to its source, but also to other artifacts in the lifecycle such as tests, use cases and project planning, we will be able to accomplish changes is a controlled manner, and anticipate to the effort required to perform a change.
Change Impact Analysis
Documenting traceability involves linking individual requirements among themselves and to other artifacts in the project.
This traceability allows analyzing in detail the impact of a change and find out which other requirements or features of the product are affected, which tests need to be executed again, or which stakeholders need to be notified of this change.
End-to-end traceability will mean the difference between an impact analysis based on assumptions and guesses, and accurate and documented information.
A frequently used technique to document bi-directional links are traceability matrices. Matrices display elements both in column and row headers, and each cell indicates whether the elements in the corresponding column and row are traced or not, and the direction of the trace, if relevant. These matrices allow us to perform a graphical analysis of the traceability.