Bibliometrics: Journal Impact
Use of Journal Metrics
Journal metrics are not appropriate for evaluating an individual article or researcher as they are a journal level indicator.
These metrics can be a broad indicator or guide to the general visibility of a journal. Journal metrics can also be used as a collection development tool for libraries when evaluating which journals to purchase or subscribe to.
The average citation level of a journal is an extremely limited indicator, and is not a replacement for expert, qualitative assessment of the journal. The distribution of citations is typically skewed, therefore using the mean is problematic. Many articles published in "high impact" journals receive very few or indeed no citations at all. Many factors can influence citation rates such as language, journal history, publication schedule, and subject specialty and scope.
Other factors which can affect a journal's ranking or metrics include:
- article type(s)
- changes in journal format
- title changes
- cited-only journals (i.e. whereby references from a journal (including self-citations) are not included in the dataset)
Many of the journals in Web of Science and Scopus are English-language from North America, Western Europe and Australia. Irish journals in many research areas can be underrepresented.
Review journals and original research journals are treated the same even though the citation patterns of these types of articles differ.