How good is a journal? What is its reputation? How does it compare to other journals in the same field? To attempt to answer these questions, many people resort to journal-level metrics, the best known of which is Journal Impact Factor (JIF).

JIFs are published in Journal Citation Reports (available via GC library). JIFs are based on citation data from Web of Science (available via GC library), which indexes 20,000+ journals — a very large number of journals, to be sure, but certainly not all journals or even all reputable journals. Therefore, not all journals receive JIFs, and not having a JIF is not necessarily a reflection of a journal’s quality or rigor. 

A journal’s impact factor for a given year is the number of citations made in that year to the journal’s articles from the two prior years, divided by the journal’s total number of articles from those two prior years. For example, here is how a journal’s 2024 JIF is determined, written as an equation:

Put differently, a journal’s 2024 JIF is the average number of times articles published in that journal in 2022 and 2023 were cited in 2024.

Because of the aforementioned disciplinary differences in citational practices, there is no such thing as an objectively “good” or “bad” JIF, and it’s impossible to judge a journal’s JIF in a vacuum. Its JIF is only meaningful in context — i.e., relative to the JIFs of other journals in the same field.

Unfortunately, JIFs are often improperly used as shorthand for journal quality. As a result, a JIF can have an outsize effect on the reputation of a journal, and of the authors who publish in it. Not surprisingly, some journals chase higher JIFs by favoring articles on “hot” topics likely to generate buzz and thus citations within two years of publication. Some even attempt to manipulate JIFs through unethical practices such as coercive citation (i.e., pressuring authors to add citations to other articles from the same journal).

Another citation-based journal metric is SCImago Journal Rank (SJR), a cost-free alternative to Journal Impact Factor. The formula for SJR is similar to the formula for JIF but is also weighted according to the supposed importance of the citing journal (where “importance” is determined by a complicated recursive calculation). Another key difference between JIF and SJR is that SJR is based on citation data from Scopus, another expensive library database (not available via GC library; available at some other CUNY libraries). 

All told, SJR-based rankings and JIF-based rankings are similar but not identical. But always remember that both systems are based on average citation rates and must not be confused for measures of quality.