See this guide by the Johns Hopkins Sheridan Libraries for more information on journal metrics and their influence on readership and recognition of scholarly research.
Journal, article, and author metrics are various mathematical formulas that have been developed to calculate scholarly impact within a discipline. Most of these formulas work by tabulating the number of citations against the total citations possible in a field or journal.
The "Impact Factor" journal metric developed by Clarivate Analytics of the Web of Science Group is the journal metric most people use when discussing journal metrics, though people also use this term when they mean the larger generic concept.
Impact factor, 5-year impact factor, immediacy index, cited half-life, Eigenfactor, Article Influence
Citations to articles from the most recent five full years, divided by the total number of articles from the most recent five full years, but weeds out journal self-citations. It also, unlike the Journal Citation Reports impact factor, cuts across both the hard sciences and the social sciences.
Google Scholar Metrics Provides h5-index and h5-median