GS includes many disciplines and sources: peer-reviewed papers, theses, books, preprints, abstracts, articles, and technical reports from academic publishes, professional societies, preprint repositories and universities, and other scholarly organizations available across the Web.
However when searching Google Scholar (GS) it is good to keep in mind some facts of it. Browsing options are quite lacking. GS does not publish information about the time span, coverage or how often the database is updated. GS as a source for citation information differs a lot from scientific citation databases like Web of Science and Scopus.
Google Scholar includes basic and advanced search options, but they are not as developed as the corresponding features in commercial databases. For example, the browsing options for variations of journal and author names are lacking.
The search result of Google Scholar is varying. It may include a link to the full text of an article, an abstract or a reference. Search results are sorted by GS ranking system. The number of citations to a particular work seems to be important part of GS ranking system. Nevertheless the GS ranking is partly unclear.
Search results of an author search for JE Hirsch. The html/pdf link on the right side provides access to the free full text of the article. The links to cited by, related articles, and other versions of the article are listed under each reference.
Source: Google Scholar <[http://scholar.google.fi/]> 20.6.2013
GS as a source for scientific citation information is inaccurate and undefinite . Instead GS citation information can be used to evaluate the societal impact of publications.
GS contains a lot of citations that are not scientific ones. That is why the sum of citations is usually much greater than the sum in Web of Science and/or Scopus. There is no information available about the time span and coverage of GS. To continue it is not possible to define the GS citations window. GS is also easy to manipulate. All the above mentioned affects on the reliability of citation information retrieved from GS.
Publish or Perish uses citation information from GS to evaluate journals and researchers.
GS search results can be imported to RefWorks directly via a link in the results display. This feature can be set up by selecting RefWorks in the bibliography management selection in the GS setting.
Setting up Refworks and other bibliography management tools is possible via the GS settings.
Source: Google Scholar <[http://scholar.google.fi/]> 20.6.2013
The import into RefWorks link is displayed for each reference in the search results.
Source: Google Scholar <[http://scholar.google.fi/]> 20.6.2013
The most important multidisciplinary databases containing citation information are Web of Sciece (WoS) by Thomson Reuters and Scopus by Elsevier. Citations can also be retrieved from Google Scholar (GS) keeping in mind the limitations of the database. GS contains a lot of non-scientific citations. The number of citations can vary a lot between Web of Science, Scopus and especially GS.
In addition, there are some field specific databases which contain reference information such as Chemical Abstracts (SciFinder), CiteSeerX and MathScinet.
Table below: Comparison of WoS, Scopus and GS
Feature |
Web of Science (more information) |
Scopus (more information) |
Google Scholar (more information) |
---|---|---|---|
Availability |
subscription based |
subscription based |
freely accessible |
Number of journals |
22 000 peer-reviewed journals |
23 500 peer-reviewed journals |
information is not publically available |
Other contents |
conference proceedings, books |
conference proceedings, professional magazines, patents and book series |
books, pre-prints, theses and dissertations, and webpages |
Main disiplines |
Natural Sciences, Technology, Social Sciences, Fine Arts and Humanities |
Physics, Technology, Health Sciences, Bio sciences, Fine Arts and Humanities, |
information is not publically availabale |
Time span |
from 1900 (Science), 1956 (Social Sciences) and 1975 (Arts and Humanities), accessble |
records back to 1788
|
information is not publically availabale |
Up-dates |
weekly |
daily |
information not publically available, but more or less monthly |
Collection policy |
public |
public |
information not publically available, contracts with most significant publishing houses |
Citation analysis |
Citation Report -tool |
View citation overview -tool |
search report with a 'Cited by' link, giving all pulications which cite the publication in question |
Time span of citation information |
from 1900 (Science), from 1956 (Social Sciences) and from 1975 (Arts and Humanities); citation statistics available at Oulu University Library for the whole period, but the referencing articles only available from 1975 |
cited references dating back to 1970 |
information is not publically availabale |
Web of Science | Scopus | Google Scholar | |
Indicators | Journal Citation Reports: - Article Influence (AI) - Eigenfactor - H-index - Immediacy Index - Impact Factor (IF) |
- H-index - Raw impact per publication (RIP) - SCImago Journal Rank (SJR) - Source normalized impact per paper (SNIP) - Field-Weighted Citation Impact |
- H-index |
Tools | - Journal Citation Reports - Eigenfactor - ScienceWatch |
- Scival - SCImago Journal and Country Rank - CWTS Journal Indicators |
- Publish or Perish |
University rankings |
- Shanghai Ranking eli Academic Ranking of World Universities (ARWU) - Review of the state of scientific research in Finland by The Academy of Finland |
- Times Higher Education World University Rankings - QS World University Rankings - Webometrics |
- Webometrics |
Researcher profile | - ResearcherID | - Scopus Author Identifier - also Scopus Affiliation Identifier |
- Google Scholar Profile |
From the perspective of citation analysis, what matters most, is the number of records enhanced by cited references and the total number of cited references included in the database used. In addition to contributing citation data, citation enhanced databases may serve as a platform providing the analytical tools for bibliometric analysis. Both of these contributions are beset with several methodological and technical difficulties, including limited coverage of the scholarly literature, inconsistent and inaccurate data, and limited facilities for browsing, searching and analyzing data. Most of these difficulties arise because bibliographic databases are primarily designed for information retrieval and bibliometric analysis represents only a secondary use of the systems.
Both Web of Science and Scopus have master records with cited references, and they show the bibliographic and reference details of the citing records. Web of Science is available in many different versions regarding years of coverage and citation indexes included in the subscription of the user's institution. Web of Science always includes all the cited references for every record created, irrespective of the publication year and subscription. Scopus includes cited reference information for records of papers published from 1970 onward.
Google Scholar's coverage is unknown and might be uneven across different fields of science. Additonally, older publications are poorly covered. To continue non-scholarly literature and citations are included.
Google Scholar does not automatically create profiles for researchers. However, they can create a Google account and collect all their articles found in Google Scholar to their My Citations page. The profile can be made public or kept private.
Benefits of a profile:
More information:
http://scholar.google.fi/intl/en/scholar/citations.html
Slide show guide:
http://www.slideshare.net/SarahG_SS/how-to-set-up-your-google-scholar-profile-google-scholar-citations
Video guide:
https://www.youtube.com/watch?v=cV4N6pl1FgU
7 ways to make your Google Scholar Profile better:
http://blog.impactstory.org/make-google-scholar-better/
Google Scholar: Limitations and criticism
http://en.wikipedia.org/wiki/Google_Scholar#Limitations_and_criticism
Example: Profile of David Tse, a researcher in information technology. (Source: Google Scholar, 23.3.2012.)