Impact factors compared
The most well known metric for a journal is perhaps the 2 year impact factor, found in Journal Citation Reports. However, there are other similar metrics available. This page outlines the difference between the metrics that are available in our databases.
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Databases with bibliometric information based on citation analysis
The databases shown in this table can be used to check journals for their relative importance within a discipline; to rank at departmental or country level; or for authors to select journals for their future publications.
You can find important information on problems with the application of the impact factors in these publications, among others:
- Wenn das Undurchschaubare zum Maß wird: Probleme und Schwankungen des Impact Factor, P. Heidenkummer (2013)
- Bibliometrie: Das Leidener Manifest zu Forschungsmetriken, Diana Hicks u.a. (2015)
- Beat it, impact factor! Publishing elite turns against controversial metric, Ewen Callaway (2016)
- Comparing the impact factor and Scopus CiteScore, Carl T. Bergstrom und Jevin West
|
Database |
Journal Citation Reports - Impact Factors |
SJR SCImago Journal & Country Rank |
SNIP - Source Normalized Impact per Paper |
|---|---|---|---|
|
Access |
Charité-License: |
Free access: |
Free access: |
|
Subject area |
Science, engineering, medicine, and social sciences |
Science, engineering, medicine, and social sciences |
Science, engineering, medicine, and social sciences |
|
Sources / evaluated journals |
ca. 11.500 Journals, Conference proceedings |
ca. 18.000 journals, Conference proceedings and book series |
ca. 18.000 journals, Conference proceedings and book series |
|
Based on data from |
Web of Science |
Scopus |
Scopus |
|
Description |
Impact Factor indicates the average citation rate of a journal's articles in a given year. It can serve as an indicator of the "relative importance" of a journal within a discipline. |
SJR is comparable to the JCR impact factor. However, the calculation of the SJR includes a weighting for the prestige of a citing journal. |
SNIP is an indicator of the average citation effect for articles in a journal. It takes into account the citation potential in the subject field. |
|
Calculation |
Quotient from the
- Number of citations in the JCR year - by total number of articles published in the 2 (or 5) previous years - all citations are treated the same |
SCImago uses its own mechanism for ranking scientific journals, which is based on Google's Pagerank. SJR builds on the concept that citations are not equivalent. Accordingly, citations in journals with a high SJR value are more weighty than citations from a source of lower SJR rank. |
SNIP takes into account the differences in citation practices between different disciplines. It accounts for the timeframes in which works are cited. This makes it possible to compare journals of various disciplines |
|
Evaluation period |
2 years or 5 years |
3 years |
3 years |
|
Reporting period |
from 1999 |
from 1999 |
from 1999 |
|
Updated |
Each year (Annually) |
Twice a year (Biannually) |
Twice a year (Biannually) |
|
Ranking / Comparisons |
By subject area, country and publishers |
By subject area and country |
By subject area |
|
Creator |
Clarivate Analytics (originally Thomson Reuters) |
SCImago Reseach Group and Elsevier |
Center for Science and Technology Studies (CWTS) at Leiden University (Netherlands) and Elsevier |