The future of citation analysis

The challenge is to track a work's impact when published in nontraditional forms ISI headquarters, in Philadelphia. The building's facade is supposed to evoke moving punch cards, which the company originally used to store citation data. The following page lists the top 10 cited papers from the past two years, 10 years, and of all time. In the 50 years since Eugene Garfield first proposed it, 1 the Science Citation Index has grown dramatically in size and influence. The database has expanded from 1.4 million citations in 1964 to 550 million today. Its list of source journals has grown from 613 to 15,721. And it has become a key tool for tenure, funding, and award committees. The move to a Web interface that can analyze a century's worth of literature at the click of a mouse has made the Science Citation Index, now part of Thomson Scientific's Web of Science (WOS), more useful than ever. But the same Web that has given the WOS greater and greater power has also spawned publication avenues that leave open the question of how citation analysis will evolve in the near-and long-term. Articles can be posted in multiple forms in multiple places: on the ArXiv.org preprint server, on the author's personal home page, and on the journal Web site, for instance. Those articles can be published almost immediately, giving the larger scientific community time to digest, incorporate, and ultimately cite them. The WOS is more than a literature database; it measures how often journal articles are cited by others. How do you analyze all these new types of citations? "If you're trying to figure out the impact of that article, you've got to figure out how many links go to each source and bring them together," says Michael Koenig of the Last autumn's launch of Google Scholar (GS) presents one solution. The free service searches and tracks citations to peer-reviewed literature (as the Web of Science does) and also conference proceedings, dissertations, pre-and postprint servers, and other nontraditional media. Last month, Yale University librarians Kathleen Bauer and Nisa Bakkalbasi published an analysis showing that GS yielded 4.5 more citations per paper on average in one journal, the Journal of the American Society for Information Science and Technology, for papers published in 2000, than did WOS. 2 "We found that through Google Scholar, you do get a higher average number of citing articles, than you …