Requirements Coverage
Requirements coverage measures what percentage of documented requirements have at least one associated test case verifying them, exposing gaps where a requirement exists but nothing actually checks whether it's been correctly implemented.
This is distinct from code coverage, which measures execution of source code — requirements coverage instead measures the business-facing question of whether every documented "the system should do X" has a corresponding test confirming X actually happens, independent of how that requirement happens to be implemented internally.
It's the metric a Requirements Traceability Matrix is built specifically to make visible — reading down each requirement's row and confirming at least one linked test case exists is exactly how requirements coverage gaps get identified and closed before release, rather than discovered afterward.
