The most common method for evaluating journals is bibliometric citation analysis, where the frequency of citations related to the "average article" in the journal, reflects the popularity and influence of the journal. Various citation indicators have been developed to reflect perceived quality. These can be found in journal ranking lists.
Web of Science's Journal Citation Reports (JCR) ranks journals based on citation data. JCR gives an indication of influence and impact at a category level through its Impact Factor, showing citation relationships between journals.
Scopus's Journal Metrics also ranks journals based on citation data. Like the Impact Factor, Scopus's CiteScore provides an indication of influence, ranking journals within their specific subject categories.
Impact Factor (IF) is the most commonly used measurement to determine the reputation of a journal in relation to other journals in a specific field. The calculation of IF is based on the average number of times the articles of a journal is cited in a two/five year period.
CiteScore is used to measure a journals influence and impact and is Scopus' version of the Impact Factor. Like the IF, it is calculated over a period of time (3 years), and calculates the average number of citations received in a calendar year.
SCImago Journal Rank (SJR) ranks journals included in the Scopus database. It calculates not only the number of citations to articles in journals but also takes into account the ‘quality’ of the citing journal.
Source Normalised Impact per Paper (SNIP) also ranks journals included in the Scopus database. The SNIP citation indicator is normalised according to the subject field. Citation counts in the Life Sciences tend to be higher than in the Arts and Humanities. SNIP “levels the playing field”.
Eigenfactor journal metrics computes two principal scores - the Eigenfactor Score and the Article Influence Score which take into account the quality of the citing journal, the number of articles in each issue and the different citation patterns in different disciplines. The Eigenfactor is included in the Web of Science database.
SNIP and SJR
Citescore and associated metrics
|YES - Compensates for differences in field, type and age||YES - Large number|
|YES - Meaningful benchmark is “built in” – 1 is average for a subject area||YES - Simple, easy to validate|
|NO - People may not like small numbers||YES - Communicates magnitude of activity|
|NO - Complicated; difficult to validate||NO - Affected by differences in field, type and age|
|NO - No idea of magnitude: how many citations does it represent?||NO - Meaningless without additional benchmarking|