What do Q1, Q2, Q3, and Q4 mean for journals?
Journals within each subject category are ranked by a citation metric and split into four equal quartiles. Q1 is the top 25% of journals in that category, Q2 is 25–50%, Q3 is 50–75%, Q4 is the bottom 25%. Scopus produces quartiles from CiteScore or SJR; Web of Science produces its own from JCR. A journal can be Q1 in one category and Q3 in another — the ranking is category-specific.
Detail
Category matters more than most authors realise
A journal indexed in three categories has three quartile positions. 'Q1' without a category tells you nothing. Some journals cite themselves as 'Q1' based on their strongest category while performing poorly in others.
Two databases, two rankings
SCImago (via Scopus) and Clarivate (via JCR) each produce quartile rankings, but from different data and different methodologies. A journal can be Q1 in Scopus and Q2 in Web of Science for the same period. Neither is wrong.
Practical use
For target-journal selection, Q1 and Q2 are safe for most academic requirements. Q3 and Q4 may not count for some tenure or promotion decisions, depending on institution. Always check the specific requirement, not the general 'quartile' claim.
Where to check
SCImago (scimagojr.com) is free and shows quartiles for 28,000+ Scopus journals. Web of Science quartiles require JCR access. Journal homepages sometimes display both, but only if the numbers are flattering.