SPECIAL SECTION: SCIENTOMETRICS Integrating, navigating, and analysing open Eprint archives through open citation linking (the OpCit project) Stevan Harnad* and Leslie Carr Intelligence/Agents/Multimedia Research Group, Electronics and Computer Science Department, Southampton University, Highfield, Southampton, United Kingdom SO17 1BJ better-heeled first-world institutions, secretaries or stu- The Los Alamos Eprint Archive (LANL) is a public dents could be dispatched to the journal shelves to photo- repository for a growing proportion of the current copy them). research literature in physics. The Open Citation- linking Project (OpCit) is making this resource still But turnaround times were still slow and uncertain: The more powerful and useful for its current physicist requested reprints were a long time in coming, if they users by connecting each paper to each paper it cites; came at all, in the non-first world; and even in the first, a this can be extended to all the rest of the disciplines in lot of time and resources were wasted retrieving reprints other open archives designed to be interoperable for which a glance at their abstracts or full texts, once through compliance with the Santa Fe Convention. A they were in hand, immediately revealed that it had been a citation-linked online digital corpus also allows power- false alarm. And even the relevant ‘hits’ had to be com- ful new forms of online informetric analysis that go far mitted to growing, groaning reprint shelves in labs, which beyond static citation analysis, measuring researchers’ eventually created storage, navigation and retrieval prob- usage of all phases of the literature, from pre- lems of their own. refereeing preprint to post-refereeing postprint, from Nevertheless, on balance, the increased access to the download to citation, yielding an embryology of literature that this system of monitoring and requesting learned inquiry. provided was undeniably a benefit to research and re- searchers, and increased both productivity and impact. And Gene’s other major contribution, Science Citation 0.0 Gene Garfield’s scientometrics before the Index, made it possible to monitor and measure that pro- era of online open eprint archiving ductivity and impact. Gene Garfield did not invent the ‘publish or perish’ metric of productivity, but he certainly Bibliographic citation is the mother of all hyperlinks. If fine-tuned it, with the citation-ratios of papers, authors Gene Garfield1 had come of age in the online era he and journals helping to supply promotion/tenure commit- would still have been focused on monitoring, searching, tees (as well as library serials-selection committees and accessing, linking, and analysing the research literature, sometimes even research funding committees) with a greater but he would have gone about it in a radically different variety of beans to count – supplementing the peer-review and far more powerful way. Indeed, in many respects, system itself, which, if I were not a vegetarian, I would Gene’s ideas and efforts were before their time: they call the real meat of research assessment3. wanted a PostGutenberg digital corpus all along2. Nor was citation analysis merely an evaluative metric: Current Contents helped enfranchise scientists from It was also a way of charting the present, past and future (what was then called) the third (and second) world, as course of research, sorting out the pedigrees of ideas and well as many from the less prosperous institutions of the findings, and in general doing what might be called the first world. By bringing them at least the weekly contents quantitative ‘embryology’ of knowledge. pages of the vast pre-digital journal literature to which All that, despite the obstacles that both enterprises their institutions could not afford to subscribe (and for faced in the papyrocentric Gutenberg era. Journal contents which their research activities scarcely afforded the time pages had to be gathered, photo-copied, cut/pasted, col- for the legwork of shelf-browsing in any case), Gene lated, printed and mailed around the world by the Institute made it possible to let their fingers do the walking. Re- for Scientific Information (ISI) every week; citation lists print requests could be mailed to the authors of the papers had to be laboriously retyped, compiled, analysed, printed that non-first-world scientists needed to read (or, at the and again mailed around the world in vast, heavy, cumula- tive compendia. What a different world it would have *For correspondence. (e-mail: [email protected]) been if all those data – journal contents pages and refer- CURRENT SCIENCE, VOL. 79, NO. 5, 10 SEPTEMBER 2000 629 SPECIAL SECTION: SCIENTOMETRICS ence lists – had been digital to begin with! Nothing to annual rate of 25,000 papers, with over 50,000 users photocopy, key-in, scan or cut/paste; and, if we threw in daily, and 15 mirror sites around the world. LANL also the Net along with the bytes, nothing to print or mail contains the Computing Research Repository (CoRR), either! And as long as we are digi-dreaming, why not throw which can be accessed directly through LANL or through in the full texts of all those articles too? Then it is not only the more generalized and integrated interface of the Net- ISI that no longer needs to bother with digitizing or mailing, worked Computer Science Technical Reference Library but researchers too can burn all their remaining reprint (NCSTRL)8. request cards – and free their shelves of offprints! The LANL Archive represents a substantial body of If the entire journal corpus had been digital and online, literature in physics, mathematics and computer science, far more intelligent and customized automatic alerting but the full texts are archived in a variety of forms, from services could have been devised than the mere scanning HTML to TeX to PDF to PS (Figure 1), and the first of weekly contents pages; and instead of passively waiting problem that needs to be solved is designing a way to to be alerted, researchers could actively search and navi- integrate and navigate them seamlessly. gate the entire journal literature – not only through sub- One especially important feature of full texts – their ject-, keyword-, and even full-text-searching, but also reference list – is arguably the most natural and powerful through citation-searching of a completely interlinked way of interconnecting and navigating this literature. The corpus. Searchers could even set thresholds for the impact ‘links’ are already provided by the authors themselves, and levels of the papers, authors and journals to which they users already have a long, skilled tradition of navigating wished to restrict their search. For the earlier embryologi- with them ‘offline’ (looking up the references in paper). cal stages of papers, hit-rates (down-load frequencies) for The Open Journal Project9,10 and CogPrints (http:// the preprint could supplement citation-rates for the re- cogprints.soton.ac.uk) successfully used citation linking to print. And this rich, dynamic and growing embryonic cor- interconnect a small but interdisciplinary ‘seed’ database pus would have been the database for Gene’s pioneering of full texts in the cognitive sciences with a much larger bibliometric analyses, with online user-based measures 10-year set of abstracts and their reference lists from a such as citation surfing, downloading, and hit-immediacy subset of the ISI (http://www.isinet.com/prodserv/citation/ to complement the offline author-based measures such as citsci.html ) journal citation database in the cognitive sci- publishing, citing and citation-immediacy. ences (psychology, neurobiology, computer science, lin- This digi-dream is now becoming a reality, thanks to guistics, philosophy). This work went some way toward the open archives initiative (http://www.openarchives. solving the problem of automatically recognizing and org), interoperable open archiving software (http://www. linking (within and between texts) the finite but noisy set eprints.org) and the Open Citation (OpCit) Linking Pro- of existing citation formats11–17. The reaction of users was ject (http://opcit.eprints.org). exhilaration with citation-based navigation, but frustration at accessing only abstracts. The obvious conclusion to be 1.0 The target drawn from this was that the real power of citation linking can only be realized with full-text linking. OpCit is now It is easy to state what would be the ideal online resource doing this with the LANL Archive. for scholars and scientists: All research papers in all fields, systematically interconnected, effortlessly accessi- 3.0 Citation analysis ble and rationally navigable from any researcher’s desk worldwide4,5. Citation-linking offers further benefits over and above To implement this immediately, the entire preprint and natural navigability for users and a natural unifying con- reprint literature would need to be available online in a usable, unified form. It is not, yet. But in physics a suffi- ciently large and representative subset of it is already available (see http://xxx.lanl.gov/cgi-bin/show_monthly_ submissions). So the work on that subset is now underway, and suc- cessful results based on it will not only generalize to the rest of the literature, once it is all online, but they will help to draw it all online more quickly. 2.0 The LANL Archive The subset in question is the Los Alamos National Labo- ratory (LANL) Eprint Archive (http://xxx.lanl.gov)6,7 which already contains 130,000 papers and is growing at an Figure 1. File formats in LANL Archive. 630 CURRENT SCIENCE, VOL. 79, NO. 5, 10 SEPTEMBER 2000 SPECIAL SECTION: SCIENTOMETRICS straint on interoperability and metadata processing in 4.0 Eight components of the OpCit interconnecting and integrating the literature18. It also linking project offers new ways of analysing and understanding how the literature is used: Author-end citation analysis1 already The OpCit linking project has 8 components which are reveals the offline lineages and dynamics in the growth being pursued partly in parallel, because some aspects of of research knowledge19.