Evaluation based on scientific publishing: Google Scholar

Google Scholar (GS)

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.
 

Features of GS

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 citation information

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 and RefWorks

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

Comparison of Web of Science, Scopus and Google Scholar

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,
Social Sciences

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 (RIPP)
- SCImago Journal Rank (SJR)
- Source normalized impact per paper (SNIP)
- Field-Weighted Citation Impact (FWCI) 
- 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)
- National Taiwan University Ranking (NTU)
- University Ranking by Academic Performance (URAP)
- U.S. News & World Report's Best Global Universities Rankings
- CWTS Leiden Ranking
- U-Multirank

- 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. University of Oulu currently subscribes to citation indexes and years of coverage as follows: Science Citation Index Expanded (1975 - present), Social Sciences Citation Index (1975 - present), Arts & Humanities Citation Index (1975 - present). Web of Science always includes all the cited references for every record created, irrespective of the publication year.

Scopus includes cited reference information for records of papers published from 1970 onward. There can gap in the coverage of journals in Scopus.

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.

Researcher profile in Google Scholar

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:

  • you can view a list of your own publications
  • statistics of citations received by the publications and tracking of citations
  • H-index of all the publications and five-year h-index
  • i10-index, i.e. the number of publications with over 10 citations
  • in Google Scholar search results public profiles are displayed as links
  • when searching by author in Google Scholar the public profile will be at the top in the search results.

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.)