A citation’s age is equal to the publication year of the citing item (i.e., JCR year) minus the publication year of the cited item. It is specifically defined as the median age of the citations produced by a journal during the JCR year. So for example, in the journal below, the Cited Half-Life is 9, so half of the citations are to items published after 2007 (9 years back from 2015), and half to items prior to 2007:Ĭited Half-Life is a good measure if you are interested in looking at a journal and finding out if older or newer material is receiving attention.Ĭonversely, Citing Half-Life looks at citations given by a journal in the JCR year.

In the JCR, Cited Half-Life is shown on the Cited Journal Graph as a grey division. If a journal has a Cited Half-Life of 4, it means the median age of citations is 4 years-half of the citations are to items newer than 4 years, and the other half are older. JCR caps Cited Half-Life at 10 years-any journal scoring over 10 years will display as >10 in the product. By definition, half of a journal’s earned citations are to items published before the Cited Half-Life, and half are to items published after the Cited Half-Life. This metric refers to the median age of the citations received by a journal during the JCR year. You’ve seen Cited Half-Life and Citing Half-Life data in Journal Citation Reports (JCR)-there’s a graph and a table of journals listed for every journal in the database with 100 or more citations-but what do they mean? How do you keep them straight between Cited and Citing? Why should you care about them?First, let’s look at Cited Half-Life.

What is a half life