New Types of Persistent Identifiers

A well-developed infrastructure for certain types of persistent identifiers (PIDs) already exists and is widely used for referencing publications, datasets and individual researchers. These identifiers are important elements of the fabric of scientific research, but there are others, and there are many ways that these elements may be linked together to add value in the evolving e-infrastructure of the European Open Science Cloud (EOSC) and beyond.

Below is the outline of a few emerging persistent identifiers types that researchers, their communities and research organizations may consider using.

Partners in the FREYA project are working with the relevant communities on prototypes of the following new types of PIDs which we have described below.

  • Grants
  • Instruments
  • Organizations
  • Research Cruises
  • Research Facilities

The community has had the ability to assign identifiers to published content and to individuals, however, a missing piece has been a comprehensive, open, and accessible organization identifier infrastructure that identifies affiliations and is independent of a particular service provider’s business needs.

The Research Organization Registry (ROR) has been spearheaded by Crossref, DataCite and California Digital Library and Digital Science and is designed to meet the particular need of identifying affiliation on researcher publications. It was launched in January 2019 and is available to use. Dryad have already adopted ROR in their repository and DataCite have integrated an affiliation identifier including support for ROR in v4.3 of the DataCite Metadata Schema. ROR consolidates other identifiers currently in use (e.g. GRID, ISNI, Crossref Funder ID, Wikidata) at a coarser granularity. Apart from ROR and GRID the source of organizational metadata for ROR, other PIDs are available to identify organizations in other spaces.

ISNI currently provides identifiers for over 700,000 organizations in its registry. The ISNI IDs are maintained in a single database which is curated by a network of Members and Registration Agencies.

ISNI has one Agency dedicated to the specific curation of organiszation identities, Ringgold, which manages around 500,000 ISNIs linked to its own proprietary Ringgold Org ID

Other identifiers have been assigned to specific kinds or organizations, in limited contexts. For instance DOIs for those that provide funding with the Crossref FunderID.

Grants (Research Awards)

The Grant Identifier initiative is being run by Crossref in conjunction with several funders including Wellcome Trust, JST, ERC and NIH. The sources of support for research is varied and the terms ‘grants’ and ‘grant identifiers’ are used inclusively here for ‘grants, endowments, secondments, loans, use of facilities/equipment and even crowd-funding’.

DOIs will be the PIDs used for Grants in this scheme.will be assigned for every grant awarded. The project’s metadata schema has been agreed and Crossref has already begun assigning DOIs to funders for their grants. Europe PMC is working on a pilot implementation of these DOIs for Wellcome Trust and some other early adopter funding organizations.


Research facilities such as neutron sources or synchrotron radiation sources are natural hubs of multidisciplinary research, and typically there is a requirement for their experimental data and records of science to be preserved. This makes a facility and important element of research data sharing and research publication workflows. There are several initiatives underway exploring PIDs for facilities:


In the natural sciences, equipment such as vessels, platforms, buoys, weather stations, sensors, sensor arrays or networks and other instrumentation are often central to data acquisition. Identifiers for vessels and platforms carrying instrumentation are relatively easily assigned, and for large-scale, unique instruments; descriptions can be published in the Journal of Large-Scale Research Facilities (JLSRF), where each article is assigned a DOI. However, assigning identifiers for devices, instruments and sensors in general is more complex, and there is a need for well-defined guidelines for the metadata.

The RDA PIDINST-Working Group has been working on generating the necessary framework for PID assignment for instruments, producing a universal metadata schema. ePIC can now be used to mint PIDs in the form of handles with the schema developed by the RDA working group. PID infrastructure provider, DataCite, plans to adjust their new schema, expected later 2020, to include fields that allow mapping the developed instrument schema to the DataCite schema. DOIs for instruments can already by minted though DataCite, however, additional instrument specific metadata is not accommodated yet and will need to be added once DataCite’s schema has been modified. Consequently, PID assignment for instruments is now possible and is expected to gain traction in natural sciences in the future.

PID assignment for instruments will facilitate the easy implementation of instruments in the metadata for both scientific data publications and journal article publications. Information about instrumentation used in research is often missing, but recently domain specific initiatives have progressed significantly on the implementation of instrument metadata. In marine research, several initiatives have recently been installed to try to tackle the inclusion of equipment in data metadata, supporting the full flow of sensor observations to archive.

Once such initiative is the US ‘Rolling Deck to Repository (R2R) which records and provides digital data generated by environmental sensor systems permanently installed on national research vessels. These R2R “Cruise-level” metadata records also include type and model of each instrument system along with file format and release status. An instrument identifier (DOI) is issued on completion of metadata records that links these to the data files generated by the instrument.

The Alfred-Wegener Institute (AWI), which coordinates German polar research, provides further solutions for equipment identification and accounting in research such as the SENSOR Information System infrastructure, to support the flow of sensor observation to archives (O2A platform).The main goal of SENSOR is to enhance the quality of published and archived data by providing complete metadata and PIDs for sensors used in the data acquisition process. SENSOR has been publicly available since 2015 as institutional repository and bi-annual release packages are being systematically implemented. In the context of an upcoming large scale project (MOSAiC), SENSOR will be used as a mandatory component by all international partners. SENSOR currently provides handles for sensor deployments with set metadata components, but will switch to DOIs, once the DataCite schema has been adapted to the new requirements.

Other new PID types

There are far more entities which can and do have PIDs – this list just provides a selection. FREYA Deliverables 3.1 and 3.2 provide a more comprehensive list of different entities which can and do have PIDs including samples, software and cultural artefacts.