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Research impact and visibility: Measuring impact

Impact

What impact can be measured?                                                                                                                                                            

  • individual, group, institution, subject area, geographic region                                  
  • article level (altmetrics)
  • publication channel methods:
    1. quantitative - journals, e.g. Impact Factor
    2. qualitative - journals, series, conferences, publishers, e.g. Publication Forum (Jufo)

Author impact

What is a H-index?

The h-index is an indicator used in academic publishing to measure the publishing activity of researchers and their scientific influence. It is determined by both the number of the researcher's publications and the number of the citations received by the publications.

H-index = number of publications (h) referenced to ≥ h.

  • The researcher's h-index is 10 if he/she has published at least 10 articles, which are referred to at least 10 times.
  • In practice you can have your h-index from the citation databases, you don’t have to count it.

How can I find out my h-index?

The researcher's h-index can be searched from the Scopus and Web of Science databases and from Google Scholar. Citations from Google Scholar can be analyzed with the free Publish and Perish program.

The h-index differs in different databases because of the content of the databases differs. Every database counts the h-index based on its publication coverage and therefore you must choose the database that is suitable for the discipline in question.

For analyzing h-index all the researcher’s publications found in the database are needed. Therefore, an up-to-date list of publications by a researcher is always required for a reliable determination of the h-index.

Researcher profile of the Google Scholar counts also non-scientific publications e.g. thesis. There might also be duplicates because of the self-archiving. Therefore h-index from the Google Scholar differs significantly from the values which are obtained from Scopus or Web of Science.

Typical for h-index

  • The higher the h-index score the more the researcher in question has received citations from their publications.
  • The h-index prefers researchers with longer career, its score doesn’t diminish.
  • You can compare researchers h-index if they work in the same field.
  • The h-index doesn’t take account the number of the writers in the papers. It means that the h-index prefers fields which have large research teams and researchers has lots of publications.
  • The h-index doesn’t classify the value of the citations nor the context of the citations.
  • The h-index may give undue weight to publications that are highly cited, although they may be central to the researcher's impact.

(Adapted from the guide of Oulu University Library)

H-index quick guides

The citation report (WoS) / overview (Scopus) provides aggregate citation statistics like:

  • total number of publications found
  • total number of times all publications have been cited (also without self-citations)
  • average number of times a publication has been cited (only in WoS)
  • h-index (Hirsch-index) additionally
  • Scopus article level metrics (Mendeley Readers, Blos posts, Tweets...)
  • WoS usage count per article (last 180 days / since 2013); Highly Cited Papers, Top Papers, Hot Papers

Journal impact

Publication Forum (in Finnish often referred to as JUFO) evaluates Finnish and foreign academic publication channels. Publication Forum operates under the auspices of the Federation of Finnish Learned Societies (TSV).

Publication Forum ratings

  • disseminate information on the impact and prestige of the scientific publication channels
  • handle humanities and social sciences more equally than citation analyses
  • are meant to evaluate large publication volumes only, not suited for the evaluation of the merits of an individual researcher
  • are updated regularly
  • the review of ratings is done once every four years by 23 field specific panels

The three-level classification rates the major foreign and Finnish publication channels of all disciplines.

Journal Citation Reports is a part of  the Web of Science database which tells the journal impact factors (JIF).

Impact Factor score

  • tells the average number of citations for each article in the journal 
  • based on two-year citation data - available five-year citation data
  • can be provided without journal self-cites
  • differences in citation patterns among disciplines are not considered
  • all citations are weighted equally regardless of the prestige of the citing journal
  • is not meant for evaluating an individual researcher

 

                       Impact factor

SJR, SNIP and CiteScore can be seen in the context of Scopus journals (Sources - Browse sources). You can compare sources.

SJR indicator (SCImago Journal Rank)

  • measures the scientific prestige of a journal among other journals
  • estimates the journal impact as the average number of weighted citations for each article in the journal
  • weights citations based on the prestige of the citing journal
  • calculated using citation data from Scopus
  • based on three-year citation data
  • takes into account all types of journal articles, not only research and review articles
  • normalizes for differences in citation behavior between subject fields
  • max 33 % journal self-citations are included

SNIP indicator (Source Normalized Impact per Paper)

  • measures the contextual citation impact of a journal
  • based on Scopus data
  • based on three-year citation data
  • takes into account research articles, review articles and conference articles, but not all publication types unlike JIF 
  • differences in citation patterns among disciplines are considered
  • possible to compare journals from different disciplines unlike JIF
  • journal self-citations are included

CiteScore

  • based on Scopus data
  • an alternative to Impact Factor
  • three-year citation window
  • besides articles and reviews takes into account in calculation also other document types such as letters or editorials

 

How to calculate CiteScore

             CiteScore

A journal has an h-index of h if there are at least h papers published in that journal that have received at least h citations each.

Typical of journal h-index...

  • an alternative to Impact Factor, opens up the possibility of evaluating the impact of a journal that is not part of the Web of Science database
  • no defined citation window
  • a rough estimate for the productivity of a journal over a long time period
  • not influenced by the fact that a few articles might have a large number of citations
  • the amount of articles a journal has published will affect somewhat the h-index score, a journal that publishes many articles will most likely get a higher h-index score
  • preferable for comparing journals within the same discipline

Journal Citation Reports also publishes Article Influence scores and Eigenfactor scores.

Article Influence (AI) score

  • tells the average impact of an article published in a journal from a five-year period after the publication of the article
  • comparable with the Impact Factor
  • calculated by dividing the Eigenfactor score of the journal by the number of articles published

Eigenfactor (EF) score

  • describes journal's total impact and is not comparable with Impact Factor
  • citations also from other sources than Thomson Reuters journals, e.g. books
  • 5 year citation window
  • adjusts differences in citation patterns among disciplines
  • accounts for difference in prestige among citing journals