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Journal rankings

Journal ranking databases evaluate citations between articles of the evaluated journals and create different key figures (bibliometric indicators) per journal within a subject area. They can be used, for example, to check journals for their relative importance within a subject area, or - as an author - to select journals for future publications.

Selected databases with bibliometric data

In the databases a restriction to Open Access Journals is possible (except in Google Scholar Metrics).

SJR - Scimago Journal & Country Rank

The freely accessible database Scimagojr.com offers, among other things, the SCImago Journal Rank (SJR, from 1999), which is comparable to the Impact Factor (IF). But, among other criteria, the SJR  includes the prestige of a journal, i.e. citations of articles from frequently cited journals increase the prestige of the journal whose articles are cited.

The data basis is the database SCOPUS (not licensed in Mannheim), a competitor product to Web of Science, in which more journals are evaluated than in Journal Citaton Reports or Web of Science. A 3-year period is used for the evaluation of citations. Self-citations are excluded. The data are updated annually in November (new annual evaluation).

The journal display shows - sorted by subject area or for individual journals - in addition to the SJR e.g. quartile, H-index, scope note with source link, average citations per publication and degree of international cooperation.

With the Country Rank, individual countries and 8 world regions can be evaluated since 1996 according to subject areas - the values, among others, are number of publications, citations per publication (average), self-citations, non-cited publications and the H-Index (number of publications h that have received at least h citations).

One of the Viz Tools is the Subject Bubble Chart, which allows, among other things, to compare the medical specialties by means of bubble charts according to various criteria.

JCR - InCites Journal Citation Reports (Clarivate Analytics)

In the database InCites Journal Citation Reports (Sciences Edition) of Clarivate Analytics, article and citation data of more than 8000 mainly English-language journals in the fields of medicine, technology and natural sciences are evaluated annually.

In addition, there is also the JCR Social Sciences Edition, which is not licensed in Mannheim.

The data are published online in July of each year and refer to the evaluations of the previous year (JCR year).

Journal Impact Factor

For a given journal, the Journal Impact Factor (IF) indicates how often the citable articles of the two years preceding the JCR year were cited on average in the JCR year. An impact factor of 1.0 thus means that each citable article of the past two years was cited once on average. The citations can be from the same journal.

Example of a  journal X in the JCR year 2006:

Note: "Citeable articles" in the denominator are usually research articles and reviews. In the numerator, on the other hand, the citations of all document types of all Web of Science-journals are counted also on the non-quotable document types such as editorials, letters, news items and meeting abstracts.

5-Year Journal Impact Factor

This value exists since JCR 2007, with the time window for citable essays extended from 2 to 5 years.

Aggregates and Median Impact Factor

The "aggregation" summarizes journals by subject area and is calculated like the Journal Impact Factor, but for all journals of a subject area. The median value refers to all Journal Impact Factors of the subject area.

Further values of the JCR (selection)

In the JCR, further indicators are determined both for individual journals and for individual subject categories.

Journal Rank in Categories

Specifies a ranking value for the respective journal in the subject area, based on the Journal Impact Factor.

Immediacy Index

The "Journal Immediacy Index" shows the average number of citations for a journal in its year of publication. It is calculated by dividing the number of citations in a year by the number of articles in that year. The citing articles can also come from the same journal.

The "Aggregate Immediacy Index" is the value for a subject area.

Cited Half-Life

The Journal Cited Half-Life is the mean age of the articles cited in the JCR year, i.e. half of the citations to a particular journal refer to articles published within the determined year value (calculated backwards from the JCR year).

An example: Journal X has a value of 7.0 years in the JCR year 2006. This means that 50% of all citations from 2006 that refer to journal X occurred between 2000 and 2006 (inclusive).

The "Aggregate Cited Half-Life" is the value for a subject area.

The higher the value, the longer the average half-life of an attachment. Less modern or less fast-moving subject areas, where the citation maximum is reached only after more than 2 years, can possibly compensate for a lower impact factor with a higher half-life by multiplying the two values, see https://en.wikipedia.org/wiki/Impact_factor (accessed on  08.05.2020).

Citing Half-Life

The journal Citing Half-Life is the mean age of the articles cited by a journal in the JCR year, i.e. half of the citations in a journal refer to articles published within the determined year value (calculated backwards from the JCR year).
An example: The journal X has a value of 7.0 years in the JCR year 2006. This means that 50% of all articles cited by articles in journal X in 2006 were published between 2000 and 2006 (inclusively).

The "Aggregate Citing Half-Life" is the value for a subject area.

  • Cave! Comments on the IF

    In order to correctly assess the value of impact factors, it is essential to consider a number of conditions and weaknesses:

    • The impact factor does not necessarily say anything about the quality or perception of an individual article, since relatively few articles in a journal receive the majority of citations!
    • Impact factors within the field of medicine vary from discipline to discipline and are not directly comparable, for example, because large or rapidly growing disciplines have more researchers and publication organs.
    • The selection of the JCR journals is solely up to the producer of the database. Mainly English language journals are evaluated. Many German language journals with peer-reviewing are not included in the JCR.
    • Non-English language journals have a relatively lower IF because of the low coverage in the JCR and because of the language barrier they receive less attention worldwide.
    • The IF can be manipulated by intentionally citing the same journal (self-citation).
    • Journals whose articles are regularly cited substantially longer than two years (longer half-life) are rated comparatively worse, see Cited Half-Life (further IF values).
    • New branches of research are cited less frequently.
    • Basic research is rated higher than clinical medicine, since it is strongly related to basic research.
    • Many citations to non-citable document types increase the IF.
    • Journals with a high proportion of reviews can have a comparatively higher IF, since reviews are cited more frequently on average than research papers.
    • Journals with free access to the full texts (open access) have a comparatively high IF.
      (Open Access in the life sciences.)

    Most of the points mentioned here are taken from the essay Dong; Loh; Mondry: The "impact factor" revisited (published on 05.12.2005).

  • AWMF propsal for the use of the IF

    The AWMF Commission "Evaluation of Performance in Research and Education" presents the AWMF position on bibliometrics in medicine (in German) on the AWMF pages on performance evaluation research (in German) - including the AWMF proposal for the use of the "impact factor" (in German) with recommendations:

    • Method for area-specific weighting
    • Doubling of the impact factor for German-language journals
    • Evaluation of publications in professional journals not listed in the SCI and SSCI
    • Evaluation of contributions in textbooks, manuals and monographs

Google Scholar Metrics

This freely accessible online service links a top 20 ranking of English-language journals per subject area or sub-sub-subject to the cited articles that are responsible for the ranking position.

The directory is created annually in July and refers to articles that have been indexed in Google Scholar for the last 5 completed years. There are some documented references to this.

For biomedicine, there are 72 subcategories in the Health and Medical Sciences category, and around 10 eligible subcategories in the Life Sciences (& Earth Sciences) category.

Sorting is according to h5-index*. By clicking on the h5-index value, the h articles of the respective journal are displayed, sorted by the number of citations (Cited by). Now you can either jump directly to the publisher's page of the desired article, or you can click on the respective cited by link and get linked article references again.

*(using 2013 as an example: h5-index is the h-index for articles published in the last 5 complete years.
It is the largest number h such that h articles published in 2008-2012 have at least h citations each
.)

A comparable JCR ranking would be the 5-Year Impact Factor.

Note when using articles: Only if you access metrics or key figures via the link on our homepage or Google Scholar page, you have access to licensed full texts from outside the faculty network as authorized user.

CiteScore

CiteScore is a metric developed by the Elsevier company, which is used to perform evaluations for most of the journals and other types of publications (> 22,600 titles) listed in the database Scopus (About Scopus). In contrast to the Scopus database (which is not licensed by the University of Heidelberg), CiteScore is accessible free of charge.

 Unlike the Journal Impact Factor, the CiteScore indicates for each title how often the articles of the three years prior to the evaluated year were cited on average in the CiteScore evaluation year. “Front matter" materials, such as editorials or meeting abstracts, are also counted in the evaluation.

Example for a  journal X in the Cite Score year 2017:

The journal display - sorted by subject area or for individual journals - shows other values besides the CiteScore, such as SNIP (Source-Normalized Impact per Paper, a value that takes into account the differences in citation customs between the different subject areas) and SJR (Scimago Journal and Country Rank, which uses an algorithm similar to the Google PageRank method to include the prestige of a journal in the calculation).

In addition to the CiteScore itself, the metric contains seven other indicators, including the CiteScore Tracker, which is calculated like the CiteScore, but for the current year, in monthly updated form.

For further information, see Elsevier's Journal Metrics FAQs.

Eigenfactor

At the University of Washington, two new evaluation criteria were developed on the basis of the JCR data to rank the JCR journals in an annual ranking according to their importance or influence. The values are explained on eigenfactor.org, but for legal reasons they are currently only available from December of a year for the previous year - they have been available in JCR since JCR 2007.
The calculations take into account, among other things, the prestige of a journal. A 5-year period is used for the evaluation of citations. Self-citations are excluded.

The Article Influence Score is a value for the average influence of the articles in a journal and is therefore comparable to the Journal Impact Factor. The average article in JCR journals has an AI score of 1, so an AI score of 5 should mean that the article in that journal has an average influence of five times the average influence.

The Eigenfactor score is a value for the importance of a journal for the scientific community. The value should be a measure of the amount of time users spend reading a journal. The self-factor score doubles if a journal publishes twice as many publications per year with the same "quality".
Since the values are very small, the Normalized Eigenfactor was introduced in order to make the values easier to read and compare. The average Normalized Eigenfactor score of JCR journals is 1, so the value 5 should mean that the journal has five times the influence.


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