Journal Impact in Databases
Journal Impact Methods
Impact Factor
The Impact Factor ranks journals based on the number of times that that journal is cited. The Impact factor uses citation data from the previous two years, from Journal Citation Reports. For more information on the Impact Factor see the Thomson Reuters website.
To find the Impact Factor for a journal use Journal Citation Reports.
Eigenfactor
The Eigenfactor also ranks journals based on the number of times that journal is cited. It uses citation data from Journal Citation Reports. The Eigenfactor uses citation data from the previous five years, and eliminates self-citations (one paper in a journal citing another paper in the same journal). For more information about the Eigenfactor see the FAQ.
To find the Eigenfactor for a journal use the search feature.
In addition to information on journal impact, the Eigenfactor site also includes some visual depictions of citation and scholarly communication trends. These can be found at the Eigenfactor website.
Article Influence
The Article Influence of a journal is a measure of the estimated influence of an article in that journal. It is based on the journal's Eigenfactor and the number of articles published by a journal over five years as compared to the total number of articles published over that same five year period. For more information about Article Influence see the detailed methods for calculating Eigenfactor and Article Influence.
To find the Article Influence for a journal use the search feature.
SJR (SCImago Journal Rank)
SJR ranks journals by their "average prestige per article." SJR is a variant of the Eigenfactor, and it factors the impact of the journals in which each journal is cited. For more information on SJR see the home page.
To find the SJR for a journal use the search feature, or browse by subject.
SNIP (Source-Normalized Impact per Paper)
The SNIP ranks journals based on the number of citations for that journal, and the total number of citations in the subject field. It is the ratio of a journal's citation count and the citation potential of its subject field. For more information about SNIP see the home page.
To find the SNIP for a journal use the search feature, or search by subject.