Journal metrics are used to assess the impact and quality of journals.
The library has included some journal metrics in the WUR Journal Browser. When assessing the impact of a journal, you should look at the different metrics to get a nuanced view of the journal’s impact.
Most journal metrics need at least two years of citation data to calculate a journal’s impact. Journal metrics indexed in Journal Citation Reports and Scopus have undergone a thorough quality control and are more trustworthy than metrics based on Google Scholar. Please note that so-called 'predatory journals' might show false metrics.
Journal Impact Factor
The Journal Impact Factor (JIF) is the number of citations received in a year by articles published in the preceding two to five years, divided by the total number of articles published in the same period. You can find journals’ impact factors in Web of Science Journal Citation Reports.
Source Normalised Impact per Paper
The Source Normalised Impact per Paper (SNIP) is the ratio of the average number of citations received by articles in a journal (categorised in a particular field), and the citation potential of the field (i.e., the average length of the reference list of articles in that field). The SNIP allows comparisons between fields with different publication and citation rates. The SNIP is calculated using Scopus data.
SCImago Journal Rank
The SCImago Journal Rank (SJR) is the average number of weighted citations received in a year, divided by the number of articles published in the previous three years. The citations received by the journal are weighted according to the subject field, quality and reputation of the journals citing the articles. With the SJR, the prestige or impact of a journal can be compared to that of other journals. The SJR is based on Scopus data and calculated by SCImago Lab.
CiteScore counts the citations received in a year by articles published in the previous three years and divides this by the number of items (articles and other content) published in those three years. Contrary to most other journal metrics, CiteScore also includes non-peer-reviewed items such as editorials, corrigenda, and announcements. CiteScore is also based on Scopus data.
The citation count is the absolute number of citations a journal received in a year. Citation counts vary widely between fields and depend on the size of the field.
Rank, percentiles, quartiles
Any of the above metrics can be used to rank journals, in general, or per subject field. Often a journal’s rank number is mentioned to show the journal’s relative impact in a field. Besides the absolute rank number, the position of the rank in terms of percentiles or quartiles is also used.