What is a citation count?
 

    A Citation Count is the number of times an article is cited by other articles. It is considered (by some) to indicate the quality of the article. If an article is cited often it must be an important or influential article. When using the Web of Science database or the Scopus database you can sort and display your search result by Times Cited so that the most highly cited work is displayed first.

    An increasing number of databases include the citation count. Unfortunately this is rarely the total number of times an article has been cited because the citing article must be included in the database. For books and most conference proceedings citation counts in databases are considered incomplete. True citation counts would be higher than those given in the databases as no database lists all articles, books, book chapters, patents or conference proceedings and their references.

    Different databases include different journals so the citation count of an article will be different in each database. Also the coverage of cited references begins in different years in different databases - for example - Scopus citation counts are not accurate for articles published before 1996. SciFinder citation counts are not accurate for articles published before 1997. Coverage begins earliest in the Web of Science. (Updated weekly)

    When comparing citation counts it is important to remember that citation patterns are different in different disciplines.

    Sometimes there are inaccuracies or variations in references. This means that they are not recorded in the citation count.

      The Web of Science Cited Reference Search will search for inaccurate citations (or mis–cites) but you must use the first author of the paper to search for them. It will also search for cited articles and books or other items that are not published within the Web of Science coverage time span or not published in one of the journals indexed by the Web of Science.

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Creating citation reports
 

    Citation Reports in Web of Science and Citation Tracker in Scopus detail citation activity (including the h-index) of a search result. You can search for the publications and citation activity of an author, research group, or institution. You must be aware of the difficulties of comprehensively searching for the publications of an author or group. You can also see the citation activity of papers published in specific subject fields. (Updated weekly)

    It is critical that citation counts be considered and compared only within a subject discipline as citation patterns vary greatly across disciplines.

    Should you use the Web of Science or Scopus?

 
Creating citation maps
 

    Citation maps in Web of Science give a colour coded visualization of the relationship between cited and citing references including second generation citations. For example – you have published a paper cited by 6 articles and these 6 articles have been cited by a further 18 articles. You can display these relationships and colour code them by author, institution, country etc. The analysis is at the paper level.

    In this example a paper written in the US was cited by papers written in 5 different countries which were cited by papers written in 2 more countries. This paper has influenced 24 papers written in 7 countries.

    citation map

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    Tutorial by Thomson Reuters

    B.D. Simboli (2008) Review of Web of Science mapping tool. Issues in Science and Technology Librarianship, Summer 2008.

 
Other databases
 

    Google Scholar is the largest bibliographic database and it covers all types of literature not just journal articles, however from a citation indexing perspective it is considered difficult and lacking in transparency. It is difficult to count the number of publications of an author or group and how often they are cited because it is very time consuming to consolidate the many duplicates. However for some subject disciplines it is the only citation indicator available.

    Pros and cons of computing the h-index using Google Scholar by Peter Jacso (2008)

    The note in Lokman and Kiduk’s informative comparison of WoS, Scopus and GS on citation counts and ranking of 25 library and information science faculty members is sobering: ‘WoS data took about 100 hours of collecting and processing time, Scopus consumed 200 hours, and GS a grueling 3,000 hours [due to].. serious limitations of GS's document parsing and citation matching algorithms which are not so good in identifying authors and matching citations.’
    Lokman I. Meho, Kiduk Yang: Impact of data sources on citation counts and rankings of LIS faculty: Web of science versus scopus and google scholar. JASIST 58(13): 2105–2125 (2007)

    Publish or Perish is a software program that retrieves and analyzes academic citations. It uses Google Scholar to obtain the raw citations, then analyzes these and presents bibliometric statistics.

    SciFinder Web gives comprehensive coverage of all aspects of chemistry, as well as research in the biomedical sciences, engineering, materials science and agricultural science. Each CAS reference has citation counts but only if citing references are from CAS. The references that come from Medline do not have citation counts and do not contribute to citation counts. SciFinder citation counts are not accurate for articles published before 1997. There is no citation report or analysis for groups of citing references.

    Publishers’ full text journal websites eg ScienceDirect, Highwire, Springerlink etc

      Cited by or Citation Maps or Referenced by newer articles are available on many publishers’ websites. Unfortunately it only finds citing articles published by the same publisher or it uses Google. It is not comprehensive and there is no citation report or analysis for groups of references.

 
Citations in books
 

    Databases like Web of Science, Scopus and Google Scholar are useful for establishing how often a publication has been cited in the journal literature, but they cannot tell you how often it has been cited in books.

    Does this matter? In many disciplines in the arts, humanities and social sciences, books are a very significant medium for publication of new research. Databases which only count citations in the journal literature are under-reporting the impact of publications in these disciplines.

    It should be possible to check for citations to a particular publication in any database which includes the full text of books (in other words, any database of electronic books). The largest such database is Google Books, but it is far from comprehensive.

      Use the Advanced Book Search screen and insert the author’s family name in the all of the words box and insert the title of the publication in the exact phrase box.
 
What is the h-index?
 

    The h-index was first proposed by JE Hirsh as a measure of research impact of a scientist in 2005 An index to quantify an individual's scientific research output:

      "The index H, defined as the number of papers with citation number greater than or equal to H, is a useful index to characterize the scientific output of a researcher."

    If your h-index is 15, you have 15 papers cited 15 times or more. If your h-index is 20, you have 20 papers cited 20 times or more. It is a measure of the number of publications published (productivity) as well as how often they are cited (impact): Productivity + Impact = Influence

    Citation reports in Web of Science and Citation Tracker in Scopus calculate the h-index of a search result. You can search for the publications of an author, research group, or institution and calculate the h-index. You must be aware of the difficulties of comprehensively searching for the publications of an author or group. No database lists all articles.

    Help Web of Science (scroll up for full details) by Thomson Reuters

    Help Scopus by Elsevier

    Tutorials

    Use the h-index measure with care. Citation patterns vary across disciplines. h-indices in Medicine are much higher than in Mathematics for example. Researchers in different disciplines can not be compared using the h-index.

    Even within the same discipline the h-index should not be used alone as a measure of research quality. Consider the following 3 researchers who have all published 10 papers and all have an h-index of 5.

     

    All researchers have an h-index of 5 - that is 5 papers cited 5 times or more.

     

    However the Average cites per paper varies markedly

     
      Researcher 1
    cites per paper    		 Researcher 2
    cites per paper    		 Researcher 3
    cites per paper
    Paper 1 100 50 15
    Paper 2 90 50 15
    Paper 3 70 45 14
    Paper 4 50 45 14
    Paper 5
    		35
    		30
    		12
    Paper 6 4 5 5
    Paper 7 4 4 0
    Paper 8 0 0 0
    Paper 9 0 0 0
    Paper 10 0 0 0
     
    Average cites per paper
    35.3
    22.9
    7.5

    Variations

    There are many variations of the h-index. Some take into account the number of co-authors, another the years the author has been publishing etc. You can see a quick summary or more detailed information about the h-index and variations.

    Statistical comparison of the h-index and variations of the h-index by Panaretos & Malesios: Assessing scientific research performance and impact with single indices

    How to boost your h-index

    An irreverent look at the h-index by James R. Williamson My h-index Turns 40: My Midlife Crisis of Impact

 
Benchmarking using citation counts
 

    It is possible to compare the citation counts of individual scientists, schools or research institutes, universities and even countries. When benchmarking there are a couple of golden rules:

    • Choose a time period to benchmark, for an individual scientist this could be whole career, last x years, or since last promotion etc.
    • Choose which publications types will be included. Journal articles and reviews, conference proceedings, patents etc.
    • Decide if you will use all publications or selected ‘top’ publications; all researchers in an academic unit or selected ‘top’ researchers
    • Decide what you are measuring – number of publications, number of cites, cites per paper, h-index
    • Decide if you will include or remove self–citations
    • Decide on whole or fractional counting. Whole counting – full counts to all co-authors; Fractional counting – proportionate counts to co–authors; weighting first author/ last author
    • Consider if disciplinary differences of citation patterns skew results

    Always ask: Do the results make sense?

    Benchmarking can be at a number of different levels Ahmed and Rafiq (1998):

    • internal level: for an academic unit to compare its progress over time;
    • external level: the academic unit comparing itself against other academic units within the same university as well as outside the university where they are not direct competitors;
    • competitive level: the academic unit comparing itself with its direct competitors in other universities; and
    • generic level: the academic unit compares itself against ‘best industry practices’ or ‘ideal’ standards.

    Calculating Citation Counts

    Essential Science Indicators (ESI) can be used to benchmark within broad subject disciplines (based on Web of Science data). You can answer questions:

    • What is the 10-year average citations per papers for field X?
    • How do I can compare the 10-year average citations per papers in a field to the citations per paper for a scientist in that field?
    • How does the total citation count for a paper compare to the average rate for its field and year of publication?
    • What percentile group does my paper fall into?
    • How can I determine if a paper is cited among the top 10% of papers in its field?

    FAQ on benchmarking papers by Thomson Reuters

    Benchmarking papers Help by Thomson Reuters

    Tutorial: Using Baselines in Essential Science Indicators: Learn how to put citation data into context using baselines from Essential Science Indicators. (Thomson Reuters)

    FAQ on benchmarking universities. (Thomson Reuters)

 
Benchmarking using other Bibliometric Analyses
 

    Most databases allow you to analyse the search result. PubMed users can use PubReMiner. Most allow you to analyse by author, year published, journal, and keyword or subject category.

    Web of Science and Scopus automatically analyse a search on a topic by

    • author (which authors have published the most on the topic)
    • institution (after Uni of Florida, UQ publishes the most on turtles)
    • country (Australia publishes the most on coral bleaching)
    • journals (which journals publish the most on the topic)
    • years (the distribution of publications over time on the topic)

    For a search of an author’s work you can analyse by

    • the co-authors of the author and co-authors’ affiliation
    • journals (which journals the author publishes in)
    • years (the distribution of publications over time)

    For a search of citations to an author’s work you can analyse by

    • who is citing the work and their affiliation (institution and country)
    • journals they are publishing in

    Citation mapping allows you to analyse up to 2 generations of cited and citing references by author, year, journal, institution, and country.