The Article Influence Score measures the relative importance or influence of the journal on a per-article basis. It is the journal's Eigenfactor Score divided by the fraction of articles published by the journal. That fraction is normalised so that the sum total of articles from all journals is 1.

The mean Article Influence Score is 1.00. A score greater than 1.00 indicates that each article in the journal has above-average influence. A score less than 1.00 indicates that each article in the journal has below-average influence.

Some journals do not publish a lot of articles but each article may be highly influential.  That means if a journal has a score of 5, it will be 5 times as influential as the average journal. The Article Influence Score is comparable to Journal Impact Factor, whereas the Eigenfactor Score is comparable to total citation counts.

Article Influence scores and Eigenfactor are calculated using data from 1997-2015.

In 2015, Annual Reviews of Immunology, had an article influence of 20.3. This means that the average article in that journal has twenty times the influence of the mean journal in the Journal Citation Reports (JCR).

Article Influence uses Thomson Reuters (ISI Web of Knowledge) citation data.

Article Influence Scores can be accessed freely at the Eigenfactor website or through JCR.

The example below shows the top five journals using Article Influence in the JCR category of Astronomy & Astrophysics.