1003/1003.1345.md

Author Identifiers in Scholarly Repositories

Simeon Warner
Cornell Information Science and
Cornell University Library
Ithaca, NY 14850, USA
simeon.warner@cornell.edu
Submitted: 2009-10-09

Abstract

Bibliometric and usage-based analyses and tools highlight the value of information about scholarship contained within the network of authors, articles and usage data. Less progress has been made on populating and using the author side of this network than the article side, in part because of the difficulty of unambiguously identifying authors. I briefly review a sample of author identifier schemes, and consider use in scholarly repositories. I then describe preliminary work at arXiv to implement public author identifiers, services based on them, and plans to make this information useful beyond the boundaries of arXiv.

1 Context

In an ideal scholarly communication system there would be tools to browse, navigate, make recommendations and assess influence based on the complete graph of all actors (people, collaborations, institutions) and all communication artifacts (articles, comments, blog posts, usage data¹). As a shorthand I will call this complete graph the publication network. Contained within it are the familiar citation, usage, co-authorship, and co-citation graphs. In recent bibliometric and usage-based work, significant progress has been made with the artifact part of this graph (see, for example the work of the MESUR project [3]). Much less progress has been made with the actor part of the graph, in part because it is much harder to unambiguously identify authors than articles.

Consider table 1 which shows the most frequently occurring lastname, initial pairs in arXiv user accounts. This illustrates one facet of the name disambiguation problem, namely that there are many authors with the same name. This is compounded by inconsistent spellings, use of initials or full first names, and even name changes. Within a single repository such as arXiv it is not usually possible to accurately answer the question “show me all the articles by this Zhang, Y”. In recent years there has been considerable work on unsupervised and supervised author name disambiguation using many different heuristic, machine learning and clustering techniques, and many different properties including co-authorship, citations and subjects/topics. While much better than naive approaches, these techniques are still far from perfect.

In a recent Nature Correspondence, Raf Aerts asked “If it is possible to have DOIs for objects (or, so they say, enough IPv6 addresses for every molecule on Earth), why is it so difficult to implement

---

¹Logically usage data would be links between actors and artifacts. However, for historical, cultural and practical reasons most usage data is treated as anonymous even though co-usage information may be extracted.

Firstname, Initial	Count
Zhang, Y	100
Lee, J	97
Wang, Y	89
Wang, J	84
Chen, Y	77
Kim, J	77
Wang, X	76
Lee, S	74
Kim, S	69
Liu, Y	69

Table 1: Most frequently occurring lastname, initial pairs in arXiv user accounts. There may be a few duplicate accounts but this indicates that nearly 100 different people named “Zhang, Y” have created user accounts at arXiv (as of May 2009).

*DAIs [Digital Author Identifiers] for authors?*” [1]. Raf had earlier hinted at part of the answer by pointing out that he has more than one identifier in Scopus [6]. As we have already discussed, it is difficult to mine existing data to disambiguate references to authors. The more fundamental part of the answer is that it is much easier to create DOIs for articles when the one owner for an article creates the one DOI for it and presents it with the article (ignoring the issue of multiple versions of articles). As authors, we are not owned by a single authority and even if an identifier were created for us at birth by the appropriate government, there would be significant privacy concerns about using it for everything. Consider, for example, concerns over the uses and misuses of social security numbers in the USA. While we want to link a single author’s works together, do we want that identity to immediately link us to all other digital information about the private life of the individual?

2 Author Identifiers

To illustrate the diversity of currently used author identifiers, table 2 shows several example schemes used in the scholarly domain. A more detailed inventory is provided on the repinf wiki [5]. The OpenID and ISNI schemes are not limited to the scholarly domain. OpenID is aimed primarily at authentication, however, if it continues to see growing acceptance it may well be a useful open system that repositories could use. It is not clear whether ISNI will develop into a widely used system. The largest efforts to create author identifiers specifically for the scholarly domain, Scopus Author Identifiers and ResearcherID, come from commercial entities and are clearly motivated by the desire to provide improved services based upon them. It is not clear how open the interfaces based on these identifiers will be, or what data about them will be openly available.

The three other examples in table 2 illustrate decreasing scopes. In the Netherlands the Digital Author Id (DAI) “is a unique national number assigned to every author who has been appointed to a position at a Dutch university or research institute or has some other relevant connection with one of these organizations” [7]. The DAI provides a join point for data in different repositories and enables services based on this combined data (e.g. NARCIS). The RePEc scheme identifies authors and is used to link their publications together within the RePEc system serving the economic

Scheme	Example	Scope	Authority
OpenID	http://samruby.myopenid.com/	People	Distributed, anyone supporting the protocol, relies upon DNS
ISNI (International Standard Name Identifier)	ISNI 1422 4586 3573 0476	People	Draft ISO standard requiring central DB operated by proposed International Agency
Scopus Author Id	7103063073	Academia	Elsevier
ResearcherID	A-1637-2009	Academia	Thomson Reuters
Digital Author Id	info:eu-repo/dai/nl/304825271	Dutch Researchers	Dutch Universities and Research Institutes
RePEc Author Service	pzi1	Economics	RePEc
arXiv Author Id	http://arxiv.org/a/warner_s_1	arXiv.org	arXiv.org

Table 2: A sample of identifier schemes used for scholarly author identifiers

community. The AuthorClaim project aims to extend the RePEc model, using the same software infrastructure, to the entire academic domain. Finally, the arXiv author identifier, described below, is local to a single repository.

The arguments above and the understanding that there are many different interests in, and uses for, author/person identities, suggest that there will be many different systems and multiple identities for each author. In the scholarly communication domain there will be a patchwork of overlapping publication networks. Unless one system grows to dominate, the different patches of publication network will identify authors using different identifiers. However, it will be vastly easier to match multiple identifiers for each author than to disambiguate multiple authors with the same name. A significant aid will be the addition of assertions that link identities in different networks (e.g. Author A2 in Repository 1 is the same person as Author A4 in Repository 2) as illustrated in figure 1. This linking information might be expressed either via the Semantic Web or in repository metadata. The ability to record foreign identifiers in the author record within a repository, and the ability to match articles between repositories, will allow the joining of data across repository boundaries.

3 Author Identifiers at arXiv

There are a significant number of physicists for whom all articles, or at least all recent articles, are available on arXiv. It is not uncommon to find web homepages with a link to arXiv author search in place of a bibliography — why maintain the information in a second place when arXiv will do it automatically? Fielded author search has been used in this way for many years and has exactly the same problems of author disambiguation as text-based efforts to build the publication network.

With the introduction of user accounts, arXiv, like many other repositories, started to collect data on which user made each submission and whether he or she claimed to be an author. This start to building authority records was augmented by attempts to retrospectively associate older papers with users based on email address matching, and the introduction of facilities by which users could “claim ownership” of existing submissions. Use of the claim ownership facility was motivatedThe diagram illustrates two separate publication graphs, Repository 1 and Repository 2, which can be joined. Repository 1 (top) contains authors A1, A2, A3, P1, P2, and P5. Repository 2 (bottom) contains authors A4, A5, P3, and P4. Red double-headed arrows labeled 'JOIN A2=A4' and 'JOIN A3=A5' indicate the merging of these two graphs. In Repository 1, A1 wrote P1 and P2, A2 wrote P2, and A3 wrote P5. In Repository 2, A4 wrote P3 and P4, and A5 wrote P4. The 'cites' relationship is shown as a green arrow from P3 to P4.

Figure 1: If authors A2 and A3 in repository 1 are identified with authors A4 and A5 in repository 2 respectively, then the components of the publication graph from the two repositories can be joined. The P# nodes indicate papers.

through the introduction of an endorsement system² where users must be known as authors of a certain number of papers in order to endorse new users. Various heuristics are used to limit what papers can be claimed automatically and so far these have proved adequate to avoid incorrect claims being automatically accepted.

Demanding identification of all authors at submission time was considered impractical. For articles with one or two authors identification would not be too burdensome, but for papers with 10 or even 2500 authors³ it is clearly impractical. A solution that uses arXiv administrator effort to deal with each article is also impractical because just two administrators handle all user queries relating to arXiv’s 58,000 submissions/year — most submissions must be entirely automated. We thus decided on an approach that will create useful services based on a public author identifier which we internally link to our user records. We hope that by providing useful services our users will be motivated to further improve the authority records on which these services depend.

3.1 Author URI and Services

We have opted for a web-centric approach using Linked Data [2] style HTTP access. Each arXiv author identifier is a unique URI (e.g. http://arxiv.org/a/warner\_s\_1) which supports HTTP content-negotiation. These URIs are designed to be human copyable and are based on an ASCII dumb-down of the author name. By default, or if selected via content-negotiation headers, the arXiv author URI redirects to an HTML page listing all arXiv publications authored by the given individual based on our user records. An example HTML page is shown in figure 2. In cases where

²http://arxiv.org/help/endorsement

³Articles from high-energy physics collaborations often have many authors. See, for example, the recent ATLAS collaboration paper http://arxiv.org/abs/0901.0512 with > 2500 authorsFigure 2: HTML screen returned when an arXiv author id is accessed and HTTP content negotiation results in HTML, or HTML is explicitly requested by appending .html to the author id (http://arxiv.org/a/kurtz\_m\_1.html)

the author-article associations are complete this facility already solves the problem of name collision in arXiv author search and so provides a more reliable link than our text-based author search. To allow the data to be used by other applications or to allow display or monitoring with a feed reader, the list of articles associated with an author id is also available as an Atom feed. Figure 3 shows that same data as figure 2 but rendered from the Atom feed. As of September 2009 we see about 300 different author id URIs being accessed per week to return HTML pages or Atom feeds.

A list of articles on the arXiv site is still one click away from the user's homepage. We thus provide JavaScript code, which we call the myarticles widget, that a user may include in their personal homepage to dynamically include an up-to-date publication list from arXiv. Various formatting options are provided and the content may be styled using CSS. Figure 4 shows two screen shots from early adopters of the myarticles widget. This facility is based upon a content-negotiated request for an Atom representation of the arXiv author id resource which results in a machine readable Atom feed of paper information (in the same format as the arXiv API⁴).

arXiv's second use of arXiv author ids is to leverage this automatically generated and updated list of publications to lower the effort required to integrate arXiv papers into social networking sites. Facebook was chosen as the first site to work with but the OpenSocial API is also being investigated. Once the arXiv Facebook application has been told the association between a user's Facebook account and their arXiv author identifier, a list of publications is immediately available as either a panel or a tab on their Facebook profile as shown in figure 5. All title, author list, abstract and linking information is automatically imported from arXiv. New or old publications may be reported in the user's feed, with optional comments, and thus show up in friends' news feeds. This application was released in March 2009 and sees approximately 600 users per week as of September 2009. Use is steady and increasing, but there is not rapid adoption. We continue to experiment with new facilities and modes of interaction.

⁴http://arxiv.org/apiFigure 3: Web browser (Firefox) rendering of the Atom feed returned when an arXiv author id is accessed and HTTP content negotiation results in Atom, or Atom is explicitly requested by appending .atom to the author id (http://arxiv.org/a/kurtz\_m\_1.atom)

Figure 4: Two early adopter examples of use of the myarticles widget. The example on the left shows the “Google ads” formatting option used to produce a compact display in the lower left corner of the browser window. The example on the right shows the “arXiv list” formatting option which picks up local stylesheet information. In both cases the data from arXiv is seamlessly embedded in the user’s homepage.Figure 5: Example screenshots from the arXiv Facebook application. The window on the right shows a list of article titles and authors that is automatically generated because Joshua Erlich enabled the arXiv application from with his Facebook account and told it the association with his arXiv author id. Any new arXiv article owned by him will automatically be added to this list.

3.2 Helping to Build the Publication Network

arXiv is making the multiple-identifier problem one identifier worse by creating arXiv specific identifiers. Deduping articles is a key problem in bibliometrics, and we don't want to create a similar deduping problem with author identifiers. The OpenID scheme explicitly caters for multiple identifiers for a single person, and even for multiple identifiers for each persona a single person might use. Facilities to express and leverage multiple identities are described in the Yadis/XRDS document [8].

At arXiv we can go some way to addressing this problem by augmenting the Atom format machine readable authorship information arXiv exposes with correspondences between author identifiers in different schemes. The issue then is how to encourage authors to supply and update alternative identifiers associated with their account. Again we believe that the solution will be to build useful services, such as links to other systems, that depend upon this data.

Another option to encourage use of arXiv data on the relationships between authors, papers authored and identifiers in other schemes is to expose it in RDF. This is a good application for OAI-ORE Resource Maps [4] and we intend to provide OAI-ORE resource maps as another representation available from the arXiv author id. An example showing alternate name, article information and how identifiers in other schemes can be exposed is illustrated in figure 6.```

graph LR ReM((ReM)) -- "ore:describes" --> Agg((Agg)) ReM -- "HTTP conneg" --> ReM Agg -- "ore:aggregates" --> P1((P1)) Agg -- "ore:aggregates" --> P2((P2)) Agg -- "ore:aggregates" --> P3((P3)) Agg -- "ore:similarTo" --> Id1((Id1)) Agg -- "ore:similarTo" --> Id2((Id2)) Agg -- "dc:title" --> Lee["Lee, Ang
Name"] Agg -- "dc:title" --> Li["李安
Alternate name"] Id1 --> ResId["A-1637-2009
ResearcherId"] Id2 --> DAI["info:eu-repo/dai/n1/304825271
DAI"] Agg --- URI["http://.../lee_a_1"] URI --- RDF["http://.../lee_a_1.rdf"]

Figure 6: Possible OAI-ORE resource map representing the aggregation of papers by an author Ang Lee. The node ReM is the Resource Map which describes the aggregation Agg that has the author id as its URI ([http://arxiv.org/a/lee\\_a\\_1](http://arxiv.org/a/lee_a_1)). The aggregation includes the three papers (P1, P2, P3) authored by this Ang Lee. Through the `ore:similarTo` relation we also indicate two other related resources: the identities in other author id schemes. The DAI is a URI and so can be related directly as Id2. The ResearcherID is a string and must therefore be related via an additional node Id1.## 4 Conclusions

There is growing interest in accurate author identification based on explicit author identifiers. The many different commercial and non-commercial parties have varying motives and goals, and so are adopting different solutions. It seems likely that there will continue to be many different systems and multiple identities for each author. While not perfect, this situation will greatly assist the assembly of publication network data linking authors and articles which will facilitate bibliometric analyses and support new discovery tools that span multiple repositories. The implementation of author identifiers at arXiv, and of services to promote their use has been described to illustrate one approach at the repository level. Early use is encouraging but it remains to be seen how quickly the use of author identification is adopted and accepted by the scholarly community.

## 5 Acknowledgements

I am pleased to acknowledge contributions from Nathan Woody (Facebook and JavaScript interface for arXiv), Thorsten Schwander and Paul Ginsparg. This work is supported by Microsoft through a Technical Computing Initiative (TCI) Grant. This paper is based on a presentation given at Open Repositories 2009 on 18 May 2009 but with updated usage data through September 2009.

## 6 Note added in proof

There has been considerable recent activity around author identifiers, the most notable effort being ORCID (Open Researcher Contributor Identification Initiative, <http://orcid.securesites.net/>) which has significant commercial and community participation. Both Elsevier and Thomson Reuters are participants in ORCID and the resulting system may replace both Scopus Author Id and ResearcherID with a more open and more broadly adopted scheme.

## References

- [1] Raf Aerts. Digital identifiers work for articles, so why not for authors? *Nature*, 453, 2008. <http://dx.doi.org/10.1038/453979b>.
- [2] Chris Bizer, Richard Cyganiak, and Tom Heath. How to Publish Linked Data on the Web, 2007. <http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/20070727/>.
- [3] Johan Bollen, Herbert Van de Sompel, and Marko A. Rodriguez. Towards Usage-based Impact Metrics: First Results from the MESUR Project. *Proceedings of the Joint Conference on Digital Libraries 2008 (JCDL08)*, June 16, 2008, Pittsburgh, Pennsylvania, USA, 2008. <http://arxiv.org/abs/0804.3791>.
- [4] Open Archives Initiative – Object Reuse and Exchange Specifications, 2007. <http://www.openarchives.org/ore/toc>.- [5] repinf — Author identification wiki. <http://repinf.pbworks.com/Author-identification>. International Repositories Infrastructure wiki initially created to support the March 2009 International Repositories Infrastructure Workshop in Amsterdam, NL. Last accessed 2009-10-09.
- [6] Scopus Author Identifier. <http://www.info.scopus.com/>. The main Scopus service <http://www.scopus.com/scopus/home.url> and the details of author identifier are accessible from <http://tinyurl.com/yta9m7>.
- [7] SURFfoundation. Digital Author Identifier (DAI). <http://www.surfoundation.nl/smartsite.dws?ch=eng&id=13480>.
- [8] Yadis 1.0: The Identity and Accountability Foundation for Web 2.0, March 2006. <http://yadis.org/papers/yadis-v1.0.pdf>. Page listing all versions is [http://yadis.org/wiki/Yadis\\_Documents](http://yadis.org/wiki/Yadis_Documents).