Occurrence IDs

by Doug Boyer, Talia Karim (University of Colorado) and Kate Webbink (Field Museum)

Not all specimens have an occurrence ID and it is possible to leave this field blank when manually creating a new specimen record.

An Occurrence ID is intended to uniquely identify an occurrence (a taxon at a particular time and place – e.g., a single specimen or observation event). When a museum, collection, or data publisher assigns an Occurrence ID to a specimen, recommended best practice is “to use a persistent, globally unique identifier” (See http://rs.tdwg.org/dwc/terms/occurrenceID).  In addition, the Occurrence ID for a given specimen or event should be permanent. In other words, the Occurence ID for a given specimen should not change from year to year... or EVER. Not even for addressing the tiniest cosmetic issue. 

When specimens have Occurrence IDs that are permanent and globally unique, this can improve interoperability among databases that reference different kinds of data about the same specimens and informatic utility of specimen records aggregated from multiple museums.

Think of a snowflake made of diamond - diamondflake, if you will - that is the ideal analogy for an Occurrence ID. It's unique like a snowflake, but "diamonds are forever."

The official definition for “Occurrence ID (dwc:occurrenceId) is here: http://rs.tdwg.org/dwc/terms/occurrenceID