The impact factor of a periodical is a quantitative index to characterize its influence. That is, the average citation rate of each paper in a journal is actually the number of citations of a journal by all source journals in a certain year, the number of papers published in the first two years of the journal, and the number of all source papers published in the first two years of the journal.
Calculation formula: if (k) = (NK-1+NK-2)/NK-1+NK-2.
Description:
K refers to a certain year, Nk- 1+Nk-2 refers to the number of papers published in the previous two years, and Nk- 1 and Nk-2 refers to the number of cited articles in K years.
Take the calculation of if in 20 1 1 as an example:
If 20 1 1= (number of citations in this journal 20 10+ number of citations in this journal in 2009)/(number of articles in this journal 20 10+ number of articles in this journal in 2009)