Learning of the reputation of the journal from someone knowledgeable about its field is the most reliable way I can think of for someone outside the field of interest.
Impact factors seem inappropriate to me, as they can vary wildly between fields and even wildly among subfields. A more specialized, but still high quality, journal could have a much lower impact factor than a more general journal, even if the two are at roughly the same average quality. Also, some foreign language journals can be excellent despite having low impact factors for the field of the journal. This unfortunately is true even for cover-to-cover or partial translations of those foreign language journals.
You also could learn what signs to avoid. Some journals publish nonsense, and that’s usually pretty obvious after looking at a few articles. (Though, in some fields it can be hard to separate nonsense from parody.)
Beyond the previous recommendations, it’s probably better to focus on the merits of the article rather than the journal. I can immediately think of one article in particular which has a non-obvious major flaw that is published in a small journal that I consider excellent. This error should have been caught in review, but it was not, probably because catching the error requires redoing math the authors skipped over in the article. (In intend to eventually publish a paper on this error after I finish my correction to it.)
Learning of the reputation of the journal from someone knowledgeable about its field is the most reliable way I can think of for someone outside the field of interest.
Impact factors seem inappropriate to me, as they can vary wildly between fields and even wildly among subfields. A more specialized, but still high quality, journal could have a much lower impact factor than a more general journal, even if the two are at roughly the same average quality. Also, some foreign language journals can be excellent despite having low impact factors for the field of the journal. This unfortunately is true even for cover-to-cover or partial translations of those foreign language journals.
You also could learn what signs to avoid. Some journals publish nonsense, and that’s usually pretty obvious after looking at a few articles. (Though, in some fields it can be hard to separate nonsense from parody.)
Beyond the previous recommendations, it’s probably better to focus on the merits of the article rather than the journal. I can immediately think of one article in particular which has a non-obvious major flaw that is published in a small journal that I consider excellent. This error should have been caught in review, but it was not, probably because catching the error requires redoing math the authors skipped over in the article. (In intend to eventually publish a paper on this error after I finish my correction to it.)