Scimago quartiles rank journals within subject areas: Q1 is the top 25%. A Q1 journal in a niche field can have a modest impact factor and still be the best home for your paper.
Q1 by area (illustrative):
- Multidisciplinary: Nature, Science, PNAS.
- AI: IEEE TPAMI, JMLR.
- Medicine: NEJM, The Lancet.
- Computer science: check Scimago's categories, since CS values conferences over journals.
Search Scimago by your paper's keywords, filter Q1, then read each candidate's recent tables of contents. Fit beats quartile: a Q1 journal that never publishes your method will desk-reject you.
Scimago also shows citation distributions, which reveal whether a journal's quartile rests on a few blockbusters. Sources: IEEE, ACM Quartile is a starting filter, not a verdict. Your advisor's read on which Q1 journals actually read papers like yours matters more than the ranking.