Impact Factor and alternative metrics

The Impact Factor – An introduction

The Impact Factor is considered the number one ranking value for scientific journals and has become a substantial part of any journal development discussion.
Introduced in the late 1950s by Eugene Garfield and published since the 1960s by the Institute for Scientific Information® he established, the yearly Impact Factor developments are now reported in the Clarivate Analytics Journal Citation Reports®.
Impact Factors are a benchmark of a journal's reputation and reflect how frequently peer-reviewed journals are cited by other researchers in a particular year. The Impact Factor helps to evaluate a journal’s relative importance, especially when compared with others in the same field.

Calculation of the Impact Factor

The Impact Factor is basically the average number of citations counted in the Impact Factor year Y for articles published in the previous two years. Citable articles are somewhat loosely defined. In general, they include original research articles and review articles. They may also include editorials, if the editorial contains a lengthy reference list.

Springer's Impact Factor journals by subject

Click on your subject of choice to get a full list of Springer journals with an Impact Factor. In addition to the Impact Factor each journal homepage offers detailed information, such as instructions for authors, a direct link to online submission and sign-up for the Table of Contents Alert.

Alternative journal metrics

A number of journal ranking metrics have emerged over the last years in an effort to broaden the evaluation of scholarly journals. This list is a brief introduction to some of the more popular metrics.

  • 5-year journal Impact Factor: In 2009 Thomson Reuters for the first time released the new 5-year journal Impact Factor in addition to the standard 2-year journal Impact Factor. The 5-year journal Impact Factor is the average number of times articles from the journal published in the past five years have been cited in the JCR (Journal Citation Report; now published by Clarivate Analytics) year. It is calculated by dividing the number of citations in the JCR year by the total number of articles published in the five previous years. The controversy around the Impact Factor tradition has not been able to deter the Impact Factor from rising to the most important quality assessment tool in scientific journal publishing. It has to be noted that the value of the Impact Factor cannot be compared among different scientific disciplines. For instance Microbiology journals have, on average, much higher Impact Factors than Mathematics or Engineering journals. The citation patterns in these disciplines are entirely different, therefore the numerical values of their Impact Factors also differ significantly and comparisons would not yield appropriate results.
  • Eigenfactor: Similar to the 5-Year Journal Impact Factor, but weeds out journal self-citations. The citation frequency as well as the prestige of the journals is taken into account. The type of publication and the citation patterns of different disciplines are not considered. Covers over 12,000 journals worldwide, including Open Access journals and over 150,000 conference proceedings.The Eigenfactor only uses data from journals indexed by Clarivate Analytics. Learn more about the Eigenfactor.
  • Google Scholar Metrics: Google Scholar Metrics summarize recent citations to many publications. You can browse the top 100 publications in several languages, ordered by their five-year h-index and h-median metrics.Scholar Metrics currently cover articles published between 2007 and 2011 (both years included). More information about Google Scholar Metrics.
  • SJR - SCImago Journal & Country Rank:  It includes the journals and country specific indicators developed from the information contained in the Scopus® database from 1996. This metric doesn't consider all citations of equal weight; the prestige of the citing journal is taken into account.In general, self-citations are not included in the calculation. More information about SJR.
  • SNIP - Source-Normalized Impact per Paper: SNIP measures a source’s contextual citation impact by weighing citations based on the total number of citations in a subject field. It helps to make a direct comparison of sources in different subject fields.SNIP especially considers the frequency at which authors cite other papers in their reference lists, the speed at which citation impact matures and the extent to which the database used in the assessment covers the field’s literature. More information about SNIP.