What is a Persistent Identifier (PID) and why is it important?

In research projects there is a need to the information be findable, accessible and interoperable, optimising the data reuse. This information, also know as digital object, can be a person, institution, publication, dataset, codes, figures, funding body, software, research tools and other research data. It is expected that a digital object is associated with metadata and persistent identifiers (PIDs), allowing it to be stored in different repositories (Wilkinson et al. 2016; European Commission and EOSC Executive Board, 2020). Considering this processes is an important key for the research data preservation.

A PID is "a persistent reference to a digital resource" (Digital Preservation Handbook) that has the characteristics of being globally unique, persistent and resolvable (European Commission and EOSC Executive Board, 2020). The aim of PIDs is to solve the problem of persistence of access to the cited resource (Digital Preservation Handbook), avoiding access to broken and no longer existing web addresses (e.g. the location or details of the resource change). Other advantages of PIDs are that they are a primary key for identifying research resources, making possible the resource to be assigned to the correct entity despite similarities with other entities, and that they are machine-processable, which optimises the interoperability of research data (Bandrowski et al., 2015).

What are the types of PIDs?

In the research scenario, there are two main classifications for PID types according to the entities to be identified (OpenAIRE):

- Objects

o Digital Object Identifier (DOI) is for journal articles, instruments, documents, facilities, softwares, datasets, projects.

o Archival Resource Key (ARK) is for organisations, journal articles, documents, datasets, samples.

o Handle system accepts reports, publications, presentations etc depending on the research institution contributors.

o Research Resource Identifiers (RRID) is for organisations, journal articles, instruments, facilities, software, datastes, projects and samples.

o Research Activity Identifier (RAiD) is for research projects.

o Research Organization Registry (ROR) is for research organisations.

- People

o Open Researcher and Contributor ID (ORCID) is for researchers, authors, contributors.

o International Standard Name Identifier (ISNI) is for researchers, inventors, writers, artists, visual creators, performers, producers, publishers, aggregators, etc.

Why consider the use of multiple PIDs?

A research project involves different actors and entities, such as the funding agency, the research performing organisation, the researcher contributor and the research data or output platforms. The use of PIDs facilitates the interlocution of the research cycle, as it can be incorporated into the grant application and review, grant award, project registration, output submission, output publication, output registration, content notification and the final report of it processes.