A journal's impact is measured using different methodologies depending on the chosen tool, but has traditionally been based on the number of citations to articles in the journal over a period of time in comparison to other cited journals in a defined group.
These measures fall into two broad categories:
- unweighted — all citations are given the same consideration
- weighted — some citations are considered worth more than others
The best known measure of impact is the Journal Impact Factor developed by Eugene Garfield and measured using the Journal Citation Reports database. Other tools have since been developed in order to address some of the limits of this particular method. With a new shift toward article level metrics, there is growing debate as to the appropriateness of journal impact factors in promotion and tenure decisions.
Tools you can use
- JCR Journal Impact Factor »
Using the Journal Citation Reports database (containing journals indexed in the Web of Science) you can compare the Impact Factor for journals within a defined subject category. A more detailed description and links to online tutorials.
- SCImago Journal Rank (SJR) »
Using an algorithm based on Google's PageRank, the SJR indicator shows the visibility of journals in the Scopus database from 1996 on. This visibility is calculated by assigning weights to bibliographic citations based on the "importance" of the journals that issued them.
- Scopus Journal Analyzer »
Allows you to select up to 10 journals in a specific field. The results are uploaded into graphs, making it possible to see how journals are performing relative to each other.
- Google Scholar Metrics »
Provides browsable lists of the top 100 journals indexed in Google Scholar by language, with titles ordered by their five-year h-index and h-median metrics. Lists of top 20 journals titles for subject areas are also available.
- Eigenfactor »
Eigenfactor.org is an academic research project that uses network analysis and information theory to develop methods for evaluating the influence of scholarly periodicals and for mapping the structure of academic research.