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Bibliometrics and Altmetrics: Measuring the Impact of Knowledge

This guide includes information on which of the databases contain citation measures that can be used to gage either an author, article or journal impact.

DEFINITION: Citation Analysis

What is citation analysis?

Citation analysis is the study of the impact and  assumed quality of an article, an author or an institution based on the number of times works and/or authors have been cited by others.

Why use it?

♦  To find out how much impact a particular article has had, by showing which other authors based some work upon it or cited it as an example     within their own papers.

♦  To determine how much impact a particular author has had by looking at his/her total number of citations.

♦  To find out more about a field or topic; i.e. by reading the papers that cite a seminal work in that area.

Source: Citation Analysis Guide from University of Michigan. Authors: Paul Grochowski, Barbara Shipman, Deirdre Spencer, Sue Wortman.

Overview of Different Metrics Databases


Web of Science (WOS)

Google Scholar       

Subject Focus         

Science, Technology,
Social Sciences, Arts & Humanities

Medical, Scientific, Technical, Business, 
Social Sciences, Arts & Humanities


Composed of 3 citation indexes:

Science Citation Index Expanded — back to 1900

Social Sciences Citation Index – back to 1956

Arts & Humanities Citation Index – back to 1975

Conference Proceedings -- back to 1990

Selections from PubMed, IEEE, American Institute of Physics, proceedings of the National Academy of Sciences,, American Medical Association and other medicine journals, Ingenta, SpringerLink,Wiley Interscience, Cambridge journals, Taylor and Francis, Sage Publications, Blackwell-Synergy, OCLC First Search and others

Open access journals and pre-prints

Online dissertations and theses


Over 12,000 journals


Time Span

Some journal files going back to 1900; see above for more details

Theoretically, whatever is available on the Web



Monthly on average


Deeper back-files especially for Science Journals.

While controversial, its journal citation reports, impact factors, and h-index are most widely used.

More focused on U.S. research.

Offers citation mapping for visual presentation.

Provides a more comprehensive picture of scholarly impact as it indexes non-traditional sources such as PowerPoint and MS Word documents not covered by Web of Science.

Includes peer-reviewed papers, theses, books, abstracts, and articles from academic publishers, professional societies, preprint repositories, universities, and other scholarly organizations

Better coverage of newer materials than Web of Science.

International and multi-lingual coverage.


Can lead to low citation counts due to errors in citations provided by authors, and different citation styles used by journals leading to poor indexing.

Limited search features.

Inflated citation counts due to inclusion of non-scholarly sources such as promotional pages, table of contents pages, course readings lists etc.

Weeding irrelevant hits is time consuming.

No way to determine what sources, and time spans are covered.

Limited to what is available on the free Web.

May include non-scholarly citations like newspaper articles.

Source: Citation Analysis Guide from University of Michigan. Authors: Paul Grochowski, Barbara Shipman, Deirdre Spencer, Sue Wortman.