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Relationship Types Reference
The eight semantic relationships a crosswalk mapping can express.
For guidance on choosing between them with worked examples, see Crosswalk Relationship Types.
The eight types
| Type | Reads as | Definition |
|---|---|---|
equivalent | Control equals requirement | Direct one-to-one functional and control-objective equivalence |
subset | Control is narrower | The control covers part of the requirement; more is needed |
superset | Control is broader | The control satisfies this requirement and others besides |
intersection | Partial overlap | Partial overlap in mechanism or scope; gaps on both sides |
compensating | Alternative mechanism | A different mechanism mitigating the same underlying risk |
supporting | Defence in depth | A secondary or foundational control reinforcing the primary one |
related | Thematic reference | Contextually connected, but not addressing the objective |
no_match | Assessed as not matching | A considered conclusion that this control does not address this requirement |
Legacy aliases
Older or imported datasets may carry these values. They normalise on entry:
| Legacy value | Normalises to |
|---|---|
equal | equivalent |
full | equivalent |
partial | intersection |
Any unrecognised value normalises to related.
Reading coverage from relationship type
Relationship type does not drive satisfaction — that comes from evidence, coverage and effectiveness. It drives how a human should read the coverage picture.
| An obligation whose only mapping is... | Read it as |
|---|---|
equivalent, approved, control effective | Addressed by design and operating |
subset | Part of the obligation is unaddressed by design |
intersection | Both a coverage gap and a scope mismatch exist |
compensating | A deviation exists; check whether it is formally accepted |
supporting only, no primary mapping | Nothing addresses the objective directly |
related only | Nothing addresses the objective at all |
no_match only | Deliberately unmapped |
The last three rows are worth auditing your crosswalk for
An obligation whose only mappings are supporting or related looks mapped on a count and is unaddressed in substance. A count of mappings per obligation will not surface this; a breakdown by relationship type will.
When to record no_match
A no_match record documents a considered negative conclusion. It:
- Prevents the same plausible-but-wrong mapping being re-proposed each quarter
- Documents that the question was asked
- Stops AI suggestion passes resurfacing a relationship a human has already rejected
- Gives an assessor evidence that your crosswalk is the result of analysis rather than optimism
A crosswalk with no no_match records is a warning sign
It usually means suggestions are being approved or ignored rather than assessed.