Journal impact metrics attempt to quantify the importance of a particular journal in its field, usually via a formula that takes into account the number of articles published per year and the number of citations to articles published in that journal. On this page, you will find descriptions of common journal impact metrics, as well as tools to use to find them.
1. Journal impact metrics do not assess the quality of individual articles, their importance, or usefulness! The quality and impact of the author's work may extend beyond the impact of a particular journal.
2. "To say that because a researcher is publishing in a certain journal, he or she is more influential or deserves more credit is not necessarily true. There are many other variables to consider." (Jim Testa, a researcher for ThomsonReuters Scientific in a 2008 interview)
3. Journal Impact Factor, Eigenfactor, and CiteScore cannot be used to compare journals from different subject fields.
4. Citation-based journal impact metrics are higher in disciplines in which rapid citation is the standard. Fields with a more durable literature, such as mathematics, have a much smaller fraction of short-term citations and hence lower journal impact factors.