Just as the disaggregating power of the web drove the need for the Digital Object Identifier or DOI as a means to locate specific versions of articles, chapters, books, journals, or other publications on distinct platforms,1 various unique identifiers for individual authors help to pull together a unified portrait of an author’s publications and affiliations and allow automated systems, databases, and websites to link related items to the correct “Joan Smith.” For many years, the Researcher ID®, Thomson-Reuters’ proprietary identifier used by the Web of Science database, was the leading tool for author disambiguation. Users can sign up for a Researcher ID in Web of Science (or may have one already created for them), and add or correct associated citations, research interests, or biographical information. Authors can register for or claim a Researcher ID even if their institution does not have a subscription to the Web of Science. Elsevier’s Scopus also offers a unique researcher ID, although users cannot manage their own identities and can only request corrections.
Google Scholar Citations, introduced in 2012, allows scholars to create a personal profile that can be shared publicly and displayed in search results, or kept private. Authors can add or edit their list of publications, either by retrieving them from Google Scholar or by adding them manually. The citations profile page provides a metric snapshot for all the publications associated with the author, including total number of citations to these works from across Google Scholar, for total citations, the h-index for that author (a formula for the number of papers published and the number of times cited), and the i10 index, a derivative of the h-index that examines papers cited more than ten times within the Google Scholar database. Though one can link to a public profile page, it is difficult to reuse the profile identifier on other websites or platforms.
ORCID—the Open Researcher and Contributor ID—launched in 2012, provided the interoperability that Google Scholar lacked and is a nonproprietary alternative to the Researcher ID. One’s ORCID provides each registered scholar with a unique alphanumeric code and is now commonly used on curricula vitae, in scholarly publishing workflows, and as a registration service that can link various accounts together across the web. As an open-source tool, ORCID can be integrated into a variety of web services, including altmetrics tools such as Altmetric, Impactstory, and Plum Analytics. In a nod to the ubiquity of ORCID, Thomson Reuters’ Researcher ID and the Scopus Author Identifier can now pull citations from or push citations to linked ORCID accounts, so that publication and personal details do not have to be entered in multiple places. Individuals can register for an ORCID identifier for free; institutions may join at several different levels of membership in order to be able to curate faculty accounts and to integrate ORCID information into campus reporting systems.
Approaching identities from a different angle, the Crossref organization (previously styled CrossRef) launched an open registry of funder identities in 2013 to essentially normalize funders’ names for better cross-platform reporting; its Funding Data—Crossref Meta-Data Search (known also as FundRef) of more than 14,000 registered entities is now accessible via the site’s metasearch engine. DataCite, a membership organization supported by an alphabet soup of public and private institutions from more than twenty countries—and coordinated with the International DOI Foundation and other metadata initiatives—serves as a registry and DOI clearinghouse for research data sets, an important function complementary to publication and personal IDs.