SNIP – Impact factor (since 1999)
Source Normalized Impact per Paper (SNIP) is a database published twice a year by the Leiden University's Centre for Science & Technology Studies (CWTS) in cooperation with Elsevier. It includes records with citation impact data (impact factor data) of scientific publications covered by the Scopus database from 1999 onwards.
Contents
SNIP measures a source's contextual citation impact by adjusting citations on the basis of the total number of citations in the relevant subject field. In this way, by taking into consideration the characteristics of the subject field of the source, it allows direct comparison of sources in different subject fields. The impact of a citation is valued more in the fields where citations are less frequent and vice versa. SNIP is the ratio of a source's average citation count per source and the citation potential of its subject field
In the COBISS.SI system, SNIP is divided into two main groups: SNIP Science Edition (SE), which includes data from science and technology journals, and SNIP Social Science Edition (SSE), which includes data from social sciences and humanities journals.
Display format
User: year, serial title, ISSN, impact factor (IF), country of publication, category
The following data describes the category (example: ISSN 0093-6502, year 2012):
- category (3315 – Communication)
- journal position within category, regarding impact factor (10/187)
- quarter (1)
- impact factor middle value within category (x=0.741)
- impact factor minimum value within quarter (IFmin=1.043)
- impact factor maximum value within quarter (IFmax=3.053)
Some journals are included in both SNIP databases (SNIP SE and SNIP SSE), some in several categories.
List of search prefixes and suffixes
List of search prefixes
By using the search prefixes you determine the search index you wish to search. Below is a list of search prefixes with their meaning and examples of use:
| What does it mean? | Prefix | Search example |
|---|---|---|
| Country of publication | CO= | CO=United States |
| ISSN | SC= | SC=1042-9670 |
| Category | CA= | CA=communication |
| Category SE | CN= | CN="psychiatry and mental health" |
| Category SE – code | CP= | CP=2738 |
| Category SSE | CD= | CD=education |
| Category SSE – code | CS= | CS=3304 |
| Year | PY= | PY=2011 |
| Title | TI= | TI=Astrophysical Journal Letters |
List of search suffixes
When searching in the basic index, i.e. word search, you can add search suffixes to the words in order to limit the word search to an individual search index. Below is a list of search suffixes with their meaning and examples of use:
| What does it mean? | Suffix | Search example |
|---|---|---|
| Kategorija | /CA | chemistry/CA |
| Kategorija SE | /CN | mental()health/CN |
| Kategorija SSE | /CN | cultural()studies/CD |
| Naslov | /TI | review()biophysics/TI |
Information on database and provider
Information on database:
- Database type: factual
- Coverage: data on serials impact factors
- Number of records: over 341,000
- Updated: twice a year
Information on provider:
- Provided by: Leiden University's Centre for Science & Technology Studies (CWTS) in cooperation with Elsevier
- URL: http://www.journalmetrics.com/snip.php