The Impact Factor score is calculated according to the algorithm proposed in [Garfield, 72].

Specifically, let y be the current year, thus (y-1) and (y-2) denote the previous year and the previous previous year. Further let #article_{y-1} be the number of papers published at a venue in (y-1) and #article_{y-2} for (y-2);

#citations_{y-1} be the number of citations to papers published at the venue in (y-1) and # citations _{y-2} for (y-2).

Then the impact factor if for the venue is calculated by

if[i]=(#citations_{y-1} + #citations_{y-2})/(#article_{y-1}+#article_{y-2})