Oct. 2016 -- Thomson Reuters was acquired by Onex Corporation and Baring Private Equity Asia the company is renamed Clarivate Analytics
1988 Thomson Reuters acquired the Institute for Scientific Information (ISI)
Rankings are based on the number of times articles within a journal are cited and the prestige of the journals where the citations appeared.
About 29,000 journals are ranked by SCIMago
SCIMago's ranking criteria is very similar to the Eigenfactor. The main difference is that the Eignefactor analyzes journals from Thomson's Journal Citation Reports, while SCIMago ranks journals from Elsevier's Scopus Database.
The Eigenfactor ranks the over 8,000 journals that are included inThomson Journal Citation Reports (JCR) database.
Journals are ranked by the number of other journals that cite their articles. More weight is given to citations from prestigious journals.
Cabell's Directory of Publishing Opportunities provides Impact Factors from Thomson Reuters Journal Citation Reports for many social sciences journals. Journals in the natural sciences and humanities are much less likely to appear in Cabell's Directory of Publishing Opportunities.
CitesScore from Elsevier is new freely available resource that ranks and evaluates over 22,000 journals based on how often their articles are cited by other journals. Here are some issues with this new metric:
Doesn’t always correlate with Clarivate Analytics (formerly Thomson Reuters) Impact Factor
Counts *all* document types such as letters and editorials
Elsevier, the company responsible for CiteScore, also publishes journals
CiteScore evaluates almost twice as many journals as Clarivate Analytics (Thomson Reuters) Impact Factor