21 december 2006


Scopus reviewed and compared: the coverage and functionality of the citation database Scopus, including comparisons with Web of Science and GS

At Utrecht University Library they have gone through a lot of effort to compare, the new entrant in the market for comprehensive bibliographies with citation data, Scopus with, the sleeping giant in this field, Web of Science. Their findings were presented and report was published a while back already. But it was all in Dutch. Today the English version became available. In their impressive excercise they also looked at Google Scholar and their in-house developed AI system 'Omega'. From the abstract:
Scopus is a new entrant in the market for multidisciplinary citation databases. This report analyses the coverage and functionality of Scopus and compares it to ISI's Web of Science and Google Scholar. Scopus comes out as a user-friendly product with an overall broader coverage of life sciences and physical sciences, compared to Web of Science. In social sciences coverage is not yet fully convincing. There are some volume/issue gaps in Scopus coverage as well.

From the summary:
Research results on coverage

Number of records, titles
. Scopus has almost 28 million records; the number of records in our version of WoS, at 19 million, is smaller, but the number in the full WoS (with backfiles stretching back to 1945) is larger, at 37 million. Scopus covers over 15,000 journals, versus 9,000 in WoS. Scopus covers 64% of our digital journals, as against 53% in WoS.
Period covered. Scopus is 5-15% smaller prior to 1996, and 20-45% larger than WoS after 1996 on the basis of the number of records. For publications before 1996, the coverage offered by Scopus for the various subjects is highly uneven.

Types of documents. 95% of the total database of Scopus consists of the records of descriptions of articles in journals. For the years prior to 1996, the number of non-journal articles in Scopus is low, subsequently rising to over 10% in 2005. That means that for recent years the proportion of non-journal articles is significantly higher than in WoS (4%).

Subject-specific. Scopus covers only scientific fields. WoS additionally covers the classics. The coverage provided by Scopus is 4 or more percentage points higher than that of WoS in 16 of the 18 UBU subjects on the basis of the numbers of titles of journals in the range carried digitally by the UBU. The two subjects in which WoS is stronger are both in the arts/humanities. On the basis of a number of searches, Scopus appears to be relatively weak in sociology, physics and astronomy (but caution is in order here, as further investigation is required), but very good on biomedical and geosciences.

Up-to-dateness. In terms of the inclusion of issues of journals and on the basis of the ‘progression percentage’ for coverage of the current year, there is hardly any difference between WoS and Scopus as regards the speed with which new publications are included.
Nature of data per record. Scopus has more keywords, for authors but often also from ‘controlled vocabulary’ (e.g. MeSH). Besides author keywords, WoS has no keywords from controlled vocabulary but it does have Keywords-plus: keywords generated from references.

Citation data. The difference between Scopus and WoS in terms of citation data is comparatively slight, there is a strong overlap. A count on the basis of references to 64 articles from 1995 and 2000 shows that WoS has 6% fewer references to citing articles. The difference between these two and Google Scholar is larger. While Google Scholar has 2% fewer references to these articles than Scopus, it does on average include 5 times as many ‘unique’ citing publications. For socio-economic sciences in particular, including economics, Google Scholar has many more and more unique citations.

Research result functionality

Difference in capabilities
. Scopus is slightly more versatile and has a few clear advantages in functionality in the form of default refine, the table format of results of the Citation Tracker and author identification. WoS has slightly more extensive options for citation analysis for institutions. Note: In June 2006, WoS also included a Refine tool and ISI also announced author identification for WoS.

Speed. There is above all a substantial difference between WoS and Scopus with GS, which produces virtually instant results, and also, depending on the type of search, with the Omega search engine, which is also often very quick. This can (subconsciously) be a major reason for users to choose Google Scholar. While there is little to choose between
WoS and Scopus in terms of speed, Scopus is slightly faster.

User ratings

Interviews. Heavy users from the faculties rate the clarity of the Scopus interface and refine and the citation tracker particularly highly. The majority of interviewees values Scopus more highly than Wos, but also ‘demands’ that JCR has to remain available.

Survey. A survey among 81 users shows that Scopus and WoS are less well-known than Google Scholar, but the results generated by Google Scholar are rated less highly, especially among research trainees/researchers, and among those, largely the scientific disciplines. Scopus is rated best in use, followed closely by Google Scholar. According to the respondents, WoS clearly has some ground to make up here. In terms of the relevance of the results, Scopus is likewise rated most highly of these three citation databases.

Bosman, J., I.v. Mourik, M. Rasch, E. Sieverts & H. Verhoeff (2006) Scopus reviewed and compared : The coverage and functionality of the citation database Scopus, including comparisons with Web of Science and Google Scholar. Utrecht, Utrecht University Library. 63p. http://igitur-archive.library.uu.nl/DARLIN/2006-1220-200432/Scopus%20doorgelicht%20%26%20vergeleken%20-%20translated.pdf


I just got this study in my hands. I can't find your e-mail adress?
Lars Iselid
Medical library, Umea
If you want to get into contact with (one of) the authors, mail me at mailto:j.bosman@library.uu.nl

Jeroen Bosman
Utrecht University Library
This report is useful
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