Journal-level metrics help measure the impact or importance of a journal in a field. The factors calculate the numbers of articles published per year and the number of citations to articles published in that particular journal.
The research tool Journal Citation Reports (JCR) is a tool that allows you to evaluate and compare journal impact factors using citation data, as well as review journal titles and key performance indicators in categories of academic disciplines. JCR can be accessed individually or through the library's Web of Science database.
JCR only calculates citations for publications that are indexed by Web of Science and includes few journals from the Humanities. In addition, journals need to be in existence for at least 3 years before receiving its first impact factor which may be problematic for fast moving areas.
CiteScore is a simple way of measuring the citation impact of sources available in Scopus, such as journals, by simply averaging the number of citations per document that a title receives over a three-year period. For more information about CiteScore, please see How are CiteScore Metrics used in Scopus?
CiteScore counts all documents listed in Scopus, including letters and editorials. Some in the scholarly community believe this can dilute results, but others believe all documents have the potential to attract citations and therefore should be included.
A freely accessible tool, Google Scholar Metrics, ranks journals by five-year h-indexes and h-median indexes in 9 different languages. You can sort by both broad categories and subcategories.
Google Scholar Metrics is limited to articles indexed in Google Scholar and will only display the top 20 journals for each subject category. Additionally, there is no historical data.