Journal metrics are used to measure, compare, and often rank research and scholarly publications. They can also be referred to as journal rankings, journal importance, or a journal's impact. Scholars and researchers can compare scholarly periodicals using journal metrics.
The Journal Impact Factor, created in the 1950s and available through Thompson Reuters' Journal Citation Reports, is the original citation impact metric. Other free journal metrics that have recently been created include CiteScore, Eigenfactor, Google Scholar Metrics, SCImago Journal & Country Rank (SJR), and Source Normalized Impact per Paper (SNIP).
In 1972, Eugene Garfield designed the JIF in order to rank journal according to the extent to which their articles were cited. The JIF measures the total number of citations in a given year made to all content the journal has published in the two previous years. This number is then divided by the total number of citable items published by the journal within the same time-span. Nowadays the JIF is calculated by Thomson Reuters for over 10,000 journals and is published in its yearly Journal Citation Reports
Journal Impact Factor refers to the frequency by which an article in a journal may be cited in a given year. A higher impact factor is an indication that a journal is more influential in its field of study.
Predatory journals often publish fake impact factors, or do not list one at all. You can check a journal title's impact factor via Journal Citation Reports, available through Web of Science.
•The Eigenfactor corrects for excessive self-citation by not including self-citations at all.
•The Eigenfactor that was developed by Carl and Ted Bergstrom also measures citations over 5 years. It takes the quality of citations into account by giving more weight to citations from highly cited journals. To counter practices of excessive self-citation, Eigenfactor does not include this kind of citations at all.
Scimago Journal Rank (SJR)- Scopus
The Journal h-index - uses Scopus
Google metric – uses The Journal h-index, together with some variants
Guerrero-Bote, V. P., & Moya-Anegón, F. (2012). A further step forward in measuring journals’ scientific prestige: The SJR2 indicator. Journal of informetrics, 6(4), 674-688.