FAIRsharing record for: FAIR Metric – F1 – Metadata - Identifier is globally unique

This FAIRsharing record describes: ### What is being measured?

This metric evaluates whether the identifier provided as input satisfies the EOSC-PID aligned FAIRsharing definition of global uniqueness.

### Why should we measure it?

F1 requires that metadata be assigned a globally unique, persistent and resolvable identifier. This metric is particularly concerned with the globally uniqueness aspect of GUPRIs; global uniqueness is required to prevent identifier collision across institutions, systems and domains. Otherwise, an identifier shared by multiple resources will confound efforts to describe that resource, or to use the identifier to retrieve it.
In this metric, the definition of global uniqueness follows the FAIRsharing guidance on Globally Unique, Persistent and Resolvable Identifier (GUPRI) schemas. This guidance requires that the identifier schema must use a controlled syntax/namespaces to avoid clashes; such syntax/namespaces must be governed by clearly defined Authorities. If there is any way the identifier could be created as part of another identifier system (e.g. if it is a structured series of alphanumeric characters such as P12345 (UniProt Accession Number) that could theoretically be used for other identifiers) then it is not globally unique. To fulfil this requirement in practice, it generally (but not always) requires a URL prefix of some kind.
This metric evaluates whether the identifier provided as input satisfies the FAIRsharing definition of global uniqueness. The evaluation assesses whether the identifier schema operates within a governed namespace that prevents external collision and ensures unambiguous interpretation beyond the local database context.

### Comments
For an in-depth understanding of the issues around identifiers, please see http://dx.plos.org/10.1371/journal.pbio.2001414.