The Area Score is calculated from all the citations in articles published in 2013 to articles published between 2004 and 2013. We use the Direct Influence Aggregation Model
(DIAM) published by Cornillier and Charles (Measuring the attractiveness of academic journals: A direct influence aggregation model
, Operations Research Letters, 43(2), 172–176, 2015, DOI:10.1016/j.orl.2015.01.007
). In this model, the attractiveness (i.e. the average article's influence) of a journal is defined as the weighted average of its direct influence on all other journals under consideration, to each of which is accorded a weight proportional to its own attractiveness.