Traceability matrices can be established using a variety of tools including requirements management software, databases, spreadsheets, or even with tables or hyperlinks in a word processor.

A traceability matrix is created by associating requirements with the work products that satisfy them. Tests are associated with the requirements on which they are based and the product to be tested against the requirement.

Traceability requires unique identifiers for each requirement and product. Numbers for products are established in a configuration management (CM) plan. The configuration management plan is how changes will be tracked and controlled. Traceability is a key part of managing change.

Traceability ensures completeness, that all lower level requirements come from higher level requirements, and that all higher level requirements are allocated to lower level ones. Traceability also provides the basis for test planning.

Below is a simple traceability matrix structure. There can be more things included in a traceability matrix than shown. In traceability, the relationship of driver to satisfier can be one-to-one, one-to-many, many-to-one, or many-to-many.

Traceability concept

Sample Traceability Matrix

A traceability matrix is a report from the requirements database or repository. What information the report contains depends on your need. Information requirements determine the associated information that you store with the requirements. Requirements management tools capture associated information or provide the capability to add it.

The examples show forward and backward tracing between user and system requirements. User requirement identifiers begin with "U" and system requirements with "S." Tracing S12 to its source makes it clear this requirement is erroneous: it must be eliminated, rewritten, or the traceability corrected.

Forward traceability

Backward traceability

For requirements tracing and resulting reports to work, the requirements must be of good quality. Requirements of poor quality transfer work to subsequent phases of the SDLC, increasing cost and schedule and creating disputes with the customer.

A variety of reports are necessary to manage requirements. Reporting needs determine what data should be collected in the requirements repository. Needs should be determined at the start of the effort and documented in the requirements management plan.

More discussion of the traceability matrix.

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Page updated 6/20/2010
Ludwig Consulting Services, LLC