CiteULike: JSicot's scopus

Comparison of PubMed, Scopus, Web of Science, and Google Scholar: strengths and weaknesses.

Matthew E Falagas — 2007-09-24T06:31:23-00:00

FASEB J (20 September 2007)

The evolution of the electronic age has led to the development of numerous medical databases on the World Wide Web, offering search facilities on a particular subject and the ability to perform citation analysis. We compared the content coverage and practical utility of PubMed, Scopus, Web of Science, and Google Scholar. The official Web pages of the databases were used to extract information on the range of journals covered, search facilities and restrictions, and update frequency. We used the example of a keyword search to evaluate the usefulness of these databases in biomedical information retrieval and a specific published article to evaluate their utility in performing citation analysis. All databases were practical in use and offered numerous search facilities. PubMed and Google Scholar are accessed for free. The keyword search with PubMed offers optimal update frequency and includes online early articles; other databases can rate articles by number of citations, as an index of importance. For citation analysis, Scopus offers about 20% more coverage than Web of Science, whereas Google Scholar offers results of inconsistent accuracy. PubMed remains an optimal tool in biomedical electronic research. Scopus covers a wider journal range, of help both in keyword searching and citation analysis, but it is currently limited to recent articles (published after 1995) compared with Web of Science. Google Scholar, as for the Web in general, can help in the retrieval of even the most obscure information but its use is marred by inadequate, less often updated, citation information.-Falagas, M. E., Pitsouni, E I., Malietzis, G. A., and Pappas, G. Comparison of Pub Med, Scopus, Web of Science, and Google Scholar: strengths and weaknesses.

Comparison of SCImago journal rank indicator with journal impact factor

Matthew Falagas — 2008-04-17T19:07:48-00:00

FASEB J. (11 April 2008), fj.08-107938.

The application of currently available sophisticated algorithms of citation analysis allows for the incorporation of the "quality" of citations in the evaluation of scientific journals. We sought to compare the newly introduced SCImago journal rank (SJR) indicator with the journal impact factor (IF). We retrieved relevant information from the official Web sites hosting the above indices and their source databases. The SJR indicator is an open-access resource, while the journal IF requires paid subscription. The SJR indicator (based on Scopus data) lists considerably more journal titles published in a wider variety of countries and languages, than the journal IF (based on Web of Science data). Both indices divide citations to a journal by articles of the journal, during a specific time period. However, contrary to the journal IF, the SJR indicator attributes different weight to citations depending on the "prestige" of the citing journal without the influence of journal self-citations; prestige is estimated with the application of the PageRank algorithm in the network of journals. In addition, the SJR indicator includes the total number of documents of a journal in the denominator of the relevant calculation, whereas the journal IF includes only "citable" articles (mainly original articles and reviews). A 3-yr period is analyzed in both indices but with the use of different approaches. Regarding the top 100 journals in the 2006 journal IF ranking order, the median absolute change in their ranking position with the use of the SJR indicator is 32 (1st quartile: 12; 3rd quartile: 75). Although further validation is warranted, the novel SJR indicator poses as a serious alternative to the well-established journal IF, mainly due to its open-access nature, larger source database, and assessment of the quality of citations.Falagas, M. E., Kouranos, V. D., Arencibia-Jorge, R., Karageorgopoulos, D. E. Comparison of SCImago journal rank indicator with journal impact factor. 10.1096/fj.08-107938

Using Scopus to Analyze Citations

Kimberly Hill — 2007-12-03T20:45:31-00:00

The Charleston Advisor (October 2007)

Use Google Scholar, Scopus and Web of Science for Comprehensive Citation Tracking

Lorie Kloda — 2007-09-23T19:00:11-00:00

Evidence Based Library and Information Practice, Vol. 3, No. 2. (2007), pp. 87-90.

Objective – To determine whether three competing citation tracking services result in differing citation counts for a known set of articles, and to assess the extent of any differences. Design – Citation analysis, observational study. Setting – Three citation tracking databases: Google Scholar, Scopus and Web of Science. Subjects – Citations from eleven journals each from the disciplines of oncology and condensed matter physics for the years 1993 and 2003. Methods – The researchers selected eleven journals each from the list of journals from Journal Citation Reports 2004 for the categories “Oncology” and “Condensed Matter Physics” using a systematic sampling technique to ensure journals with varying impact factors were included. All references from these 22 journals were retrieved for the years 1993 and 2003 by searching three databases: Web of Science, INSPEC, and PubMed. Only research articles were included for the purpose of the study. From these, a stratified random sample was created to proportionally represent the content of each journal (oncology 1993: 234 references, 2003: 259 references; condensed matter physics 1993: 358 references, 2003: 364 references). In November of 2005, citations counts were obtained for all articles from Web of Science, Scopus and Google Scholar. Due to the small sample size and skewed distribution of data, non-parametric tests were conducted to determine whether significant differences existed between sets. Main results – For 1993, mean citation counts were highest in Web of Science for both oncology (mean = 45.3, SD = 77.4) and condensed matter physics (mean = 22.5, SD = 32.5). For 2003, mean citation counts were higher in Scopus for oncology (mean = 8.9, SD = 12.0), and in Web of Science for condensed matter physics (mean = 3.0, SD = 4.0). There was not enough data for the set of citations from Scopus for condensed matter physics for 1993 and it was therefore excluded from analysis. A Friedman test to measure for differences between all remaining groups suggested a significant difference existed, and so pairwise post-hoc comparisons were performed. The Wilcoxon Signed Ranked tests demonstrated significant differences “in citation counts between all pairs (p < 0.001) except between Google Scholar and Scopus for CM physics 2003 (p = 0.119).” The study also looked at the number of unique references from each database, as well as the proportion of overlap for the 2003 citations. In the area of oncology, there was found to be 31% overlap between databases, with Google Scholar including the most unique references (13%), followed by Scopus (12%) and Web of Science (7%). For condensed matter physics, the overlap was lower at 21% and the largest number of unique references was found in Web of Science (21%), with Google Scholar next largest (17%) and Scopus the least (9%). Citing references from Google Scholar were found to originate from not only journals, but online archives, academic repositories, government and non-government white papers and reports, commercial organizations, as well as other sources. Conclusion – The study does not confirm the authors’ hypothesis that differing scholarly coverage would result in different citation counts from the three databases. While there were significant differences in mean citation rates between all pairs of databases except for Google Scholar and Scopus in condensed matter physics for 2003, no one database performed better overall. Different databases performed better for different subjects, as well as for different years, especially Scopus, which only includes references starting in 1996. The results of this study suggest that the best citation database will depend on the years being searched as well as the subject area. For a complete picture of citation behaviour, the authors suggest all three be used.

Google Scholar Versus Metasearch Systems

T Sadeh — 2007-05-12T15:10:46-00:00

High Energy Physics Libraries Webzine, No. 12. (March 2006)

At the end of 2004, Google launched the beta version of a new service, Google Scholar, which provides a single repository of scholarly information for researchers. Will this service replace metasearch systems? Metasearch systems are based on just-in-time processing, whereas Google Scholar, like other federated searching systems, is based on just-in-case processing. This underlying technology, along with Google Scholar's exceptional capabilities, accords Google Scholar a unique position among other scholarly resources. However, a year after its beta release, Google Scholar is still facing a number of challenges that cause librarians to question its value for scholarly research. Nevertheless, it has become popular among researchers, and the library community is looking for ways to provide patrons with guidelines for the most beneficial manner of using this new resource. Metasearch systems have several advantages over Google Scholar. We anticipate that in the foreseeable future, libraries will continue to provide access to their electronic collections via their branded, controlled metasearch system.

Impact of Data Sources on Citation Counts and Rankings of LIS Faculty: Web of Science vs. Scopus and Google Scholar

Lokman Meho — 2007-06-08T15:06:31-00:00

(2007)

A New Era in Citation and Bibliometric Analyses: Web of Science, Scopus, and Google Scholar

Lokman Meho — 2007-06-08T13:09:22-00:00

(2006)

Three options for citation tracking: Google Scholar, Scopus and Web of Science

Nisa Bakkalbasi — 2007-06-08T13:02:49-00:00

Biomedical Digital Libraries, Vol. 3, No. 1. (2006)

Researchers turn to citation tracking to find the most influential articles for a particular topic and to see how often their own published papers are cited. For years researchers looking for this type of information had only one resource to consult: the Web of Science from Thomson Scientific. In 2004 two competitors emerged ? Scopus from Elsevier and Google Scholar from Google. The research reported here uses citation analysis in an observational study examining these three databases; comparing citation counts for articles from two disciplines (oncology and condensed matter physics) and two years (1993 and 2003) to test the hypothesis that the different scholarly publication coverage provided by the three search tools will lead to different citation counts from each.