Stable identifiers

Stable identifiers are an externally stable, unique identifier for a given object. The following conditions must hold for all stable identifiers:

  • The stable identifier for a given unique entity, such as a Person or Party, must not change across different versions of the data feed.
  • A stable identifier must never be re-used for a different entity, even if the original entity is no longer in the feed.
  • The same set of stable identifiers for candidates, parties, or districts is used for both simulations, if needed, and during the election cycle.

Provide stable identifiers in the following format:

<ExternalIdentifier>
  <Type>other</Type>
  <OtherType>stable</OtherType>
  <Value>match the regex ^[a-zA-Z0-9_-]+$</Value>
</ExternalIdentifier>

Stable identifiers allow data consumers to reconcile objects in a CDF feed with other existing data repositories. In this way, in database parlance, external identifiers are a form of foreign key that allow data consumers to link objects in a CDF feed to other databases.

As an example, if "Robert Brady" is a candidate, a data consumer might not immediately link that person to "Bob Brady" in their image database. However, the CDF data and the image database could indicate that this person is legislator 01469 as identified by the Library of Congress THOMAS database. Then the data consumer can link the image with the candidate.