WHAT ARE JOURNAL CITATION REPORTS?
JCR "is a report on the citation impact of a defined set of journals [published in Web of Science (WOS)] at a given moment in time"
JCR "offers a systematic, objective means to critically evaluate the world's leading journals, with quantifiable, statistical information based on citation data." JCR looks at the impact of journals (JIF Journal Impact factor): "We capture the cited references for all content from these journals, and we link those cited references to the cited papers. This article-level citation data is aggregated to the journal-level at the end of the year to create the indicators available in JCR" (https://jcr.help.clarivate.com/Content/home.htm).
JCR includes not only publications in the WOS core collection but those in the Emerging Sources Citation Index (ESCI). ESCI journals are those "peer-reviewed publications of regional importance and in emerging scientific fields" that are worthy of noting. They do not usually have impact factors but citations to these journals within WOS are provided. These journals may well find their way into the EOS core collection.
Web of Science and Journal Citation Reports are publishedd by Clarivate.
According to JCR "In the case of academic evaluation for tenure, it is inappropriate to use a journal-level metric as a proxy measure for individual researchers, institutions, or articles"
The JIF is the citation rate to articles over a given time period for an average article in a given journal.
A journal impact factor can help reflect the relative importance of a journal in a subject area and rank journals. The IF is the average number of times articles published in the previous two years have been cited in the current year.
Many factors affect the impact factor - publishing frequency, quality of the journal's content; visibility of the journal; diversity of content; type of content eg review papers often receive more views than others. A few highly cited papers can also affect the IF.
Malan provides one of many critiques of the impact factor system: Journal impact factors - The good, the bad, and the ugly
WHAT IS A GOOD JOURNAL IMPACT FACTOR (JIF)?
In most fields, a JIF of 3 is considered good and over 10 excellent. The higher the impact factor the more highly ranked the journal is.
JIFs do however vary from discipline to discipline as the nature of publishing is different. One cannot really compare impact factors across different disciplines.
CLARIVATE JOURNAL IMPACT FACTORS - see Journal Citation Reports (based on the Web of Science collection)
ELSEVIER JOURNAL METRICS - is based on the Scopus collection
Elsevier provides 3 different or alternative metrics:
SCImago Journal & Country Rank (SJR) a free online resource that ranks journals based on citation data from the Scopus database
A journal impact factor is the citation rate to articles over a given time period for an average article in a given journal.
" The Journal Impact Factor™ (JIF) is defined as citations to the journal in the Journal Citation Reports™ (JCR) year to items published in the previous two years, divided by the total number of citable items, (i.e., Articles and Reviews) published in the journal in the previous two years." (Slide 6: https://clarivate.com/wp-content/uploads/dlm_uploads/2023/08/JCR-Reference-Guide-2023-August-update-1.pdf)
2022 citations from books, proceedings & journals (any material) in 2020, 2021
2022 JIF = -------------------------------------------------------------------------------------------------------------
number of articles and reviews published in a journal in 2020 and 2021