Journal metrics are a proxy measure used to evaluate the relative importance of a journal and identify major journals within a special field of study.
The most commonly used metrics are: Journal Impact Factor (Thomson Reuters), SJR and SNIP (Scopus), SCImago SJR (Scopus), Google Scholar Metrics.
Journal Impact Factor (developed by Eugene Garfield) provides a system for ranking journals according to citations.
The Journal Impact Factor is the average number of times articles from the journal published in the past two years have been cited in the JCR year.
The Journal Ranking shows the ranking of the current journal in its subject categories based on the Journal Impact Factor.
Not all journals have Impact Factors.
Journal Impact Factors may vary between different disciplines.
Average Journal Impact Factors may vary by factors other than the quality of the publications.
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