Singleton
One Area Code, one market family.
Where a governed Area Code does not belong to a qualifying overlay family, the market remains a single-code family.
Market family
What Is an NDS Area Code Market Family™?
Overlay-aware geography prevents the same telephone market from being counted as several unrelated places.
An NDS Area Code Market Family™ is the governed family identity NDS assigns to one Area Code or a set of strongly overlapping Area Codes that should be analyzed as one market.
Overlay family
Multiple codes, one market identity.
Codes such as 210 / 726 can represent the same practical market. The family preserves both codes while giving downstream intelligence one market key.
Governed ID
A durable key for other datasets.
The market-family ID can be reused by research, crosswalks, reports and APIs without pretending that the Area Codes themselves are proprietary.