SNIP 2016: number of citations (weighted) received in the 2016 year for the total works published 2013-2015, divided by the total work published 2013-2015.
The weighted citations according to the "citation potential" of the category of the journal (category determined according to the set of citing documents).
A citation has more value in fields where there is less frequency of citations than in areas with a tendency to receive many citations.
More information on the methodology used in CTWS, University of Leiden, creators of the indicator