Factor, if). It is a data in American ISI (institute for scientific information) JCR (Journal Citation Report).

That is, the total number of citations of papers published by a journal in the first two years of a statistical year divided by the total number of papers published by the journal in the first two years. This is an internationally accepted periodical evaluation index.

The comprehensive if- comprehensive impact factor is calculated according to the comprehensive statistical source documents of journals, doctoral and master's dissertations and conference papers.

Comprehensive IF- comprehensive impact factor mainly refers to the synthesis of arts and sciences, which is calculated based on the comprehensive statistical source literature of sci-tech journals and humanities and social sciences journals.

Both of them are based on the ratio of the total cited number of citable documents published in the first two years of the evaluated journals in the statistical year to the total cited number of citable documents published in the first two years of the journals.