In the requirements engineering field, traceability is about understanding how high-level requirements — objectives, goals, aims, aspirations, expectations, needs — are transformed into low-level requirements. It is therefore primarily concerned with the relationships between layers of information.
It enables users to find the origin of each requirement and track every change that was made to the requirements. It is required to trace every change made to the requirement. A trace of where requirements are derived from, how they are satisfied, how they are tested, and what impact will result if they are changed. Requirements come from different sources, like stakeholders, SMEs, the marketing manager and the actual user. These people all have different requirements on the product.
Using requirements traceability, it can be traced back to the person or group that wanted it during the requirements elicitation. This can be used during the development process to prioritize the requirement, determining how valuable the requirement is to a specific user. It can also be used after the deployment when userstudies show that a feature is not used, to see why it was required in the first place.
Requirements Traceability is concerned with documenting the relationships between requirements and other development artifacts such as technical requirments. Its purpose is to facilitate: the overall quality of the product(s) under development; the understanding of product under development and its artifact; and the ability to manage change.
Not only the requirements themselves should be traced but also the requirements relationship with all the artifacts associated with it, such as models, analysis results, test cases, test procedures, test results and documentation of all kinds. Even people and user groups associated with requirements should be traceable.