Evaluating Journals Using Journal Metrics: Overview

Journal metrics measure, compare, and often rank research and scholarly publications. They can also be referred to as journal rankings, journal importance, or a journal's impact. Journal metrics allow scholars and researchers to compare scholarly periodicals. 

The original citation impact metric is the Journal Impact Factor, created in the 1950s, and available through Thompson Reuters' Journal Citation Reports. More recently, a variety of other free journal metrics have been created, including CiteScore, Eigenfactor, Google Scholar Metrics, SCImago Journal & Country Rank (SJR), and Source Normalized Impact per Paper (SNIP).

Each journal ranking metric uses its own formula to determine a journal's importance to the research community. Many include counting the number of times the journal has been cited in other works. The differing formulas and methodology mean the results will differ from metric to metric. For example, an Eigenfactor score takes into consideration the size of the journal, allowing larger journals more weight, while other metrics do not take this into account. Comparing results from more than one metric will provide a better picture of the real impact of a journal.

• Review articles tend to be cited more often and can impact results.
• The practice of self-citing can impact results.
• Some journal editorial policies, such as requiring authors to add citations to articles in that journal, may inflate an impact factor.
• With metrics that compare across disciplines, disciplines with traditionally fewer journals can be at a disadvantage. Comparing journals within the same disciplines is important.
• International journal coverage can be poorly represented.
• Books or book chapters may be poorly represented, if at all.
• Different metrics use different sources to compile lists of journals. A particular metric may not include certain journals.
• Different metrics use different publication ranges, which may vary from 2-5 years.
• Different metrics focus on different disciplines or fields of study, and may not include all disciplines or fields.
• The number of citations an article has received may not predict the quality of the article.

While journal metrics are widely used in the academic and research community, they are not without controversy. These are a few articles for further reading that discuss some of the issues and challenges of measuring journal impact.