Source Normalized Impact per Paper (SNIP)
Like CiteScore, Source Normalized Impact per Paper (SNIP) is a metric available in the Scopus citation indexing database from Elsevier. The Scopus Source list and ranking metrics are freely available.
According to Elsevier, SNIP is a journal metric that "measures a source’s contextual citation impact by weighting citations based on the total number of citations in a subject field. It helps you make a direct comparison of sources in different subject fields."
Why Use SNIP?
- Free access to journal rankings (you don't need a Scopus subscription)
- Ranks more journals than Journal Citation Reports
- Covers all academic disciplines
- Measures contextual citation impact by normalizing citation values
- Takes a research field's citation frequency into account
How SNIP is Calculated
Source Normalized Impact per Paper (SNIP) is a field-normalized assessment of journal impact. SNIP scores are the ratio of a source's average citation count and citation potential. Citation potential is measured as the number of citations that a journal would be expected to receive for its subject field. Essentially, the longer the reference list of a citing publication, the lower the value of a citation originating from that publication. SNIP therefore allows for direct comparison between fields of research with different publication and citation practices.
SNIP is calculated as the number of citations given in the present year to publications in the past three years divided by the total number of publications in the past three years. A journal with a SNIP of 1.0 has the median (not mean) number of citations for journals in that field.