Glossary · Requirements and interfaces
Requirement identifier
Also known as: Requirement ID
German: Anforderungskennung
In requirements engineering, a requirement identifier is a unique, stable label assigned to a requirement so it can be referenced, traced and discussed unambiguously throughout its lifecycle, independent of its wording or position in a document.
- Systems engineering
- Data and interfaces
In one sentence
A requirement identifier is a unique, stable label that lets a requirement be referenced and traced regardless of its wording or position.
Example
The requirement 'SR-SAF-014' keeps its identifier even after it is reworded and moved to another chapter.
How it applies
- Engineering: Stable identifiers are the anchor of every Trace link; renumbering requirements breaks traceability.
- Tooling: Use identifiers generated by the requirements tool rather than chapter numbers; never reuse an identifier for a different requirement.
- Documentation: When manuals or safety information must reference requirements (for example in a traceability matrix), the documentation team should cite identifiers, not headings or page numbers.
- Exchange: When requirements are exchanged with customers or suppliers, agree how identifiers are mapped between tools, so traceability survives the exchange in both directions.
Requirement identifier vs. IRI
A requirement identifier is unique within a project or tool. An IRI (Internationalized Resource Identifier) is globally unique and resolvable, which matters when requirements are exchanged or linked in a knowledge graph.