Predatory publishers exploit the open access publishing model. They collect large fees from authors without providing the peer review services legitimate journals carry out prior to publishing papers. They rarely state their fees on initial contact, and make them hard to find on their websites.
Predatory journal websites often contain various red flags such as:
Being listed by an indexing service (CrossRef, WorldCat, Google Scholar, etc.) is no proof of worthiness. A statement by a predatory journal or predatory publisher that their articles are indexed in PubMed Central or PubMed is merely exploiting NIH-funded research requirements.
Hijacked journals were once credible, reputable journals that have been "hijacked" by predatory publishers. Features of hijacked journals can include domain name takeovers, website spoofs, and redirects.
If you've published once before, it's highly likely that a predatory journal will email you, inviting you to publish in their journal. These emails can be identified in a variety of ways, such as:
Aggressive email tactics (repeatedly emailing you even if you haven't responded)
Errors in the salutation (referring to you as Dr. when you don't have a doctorate, e.g.)
Invitation to write in a field far removed from your own
Grammatical or stylistic errors
Awkward phrasing
Excessively personalized messages from someone describing himself or herself as a physician, wanting to collaborate with you, asking you to forward their email to others at your institution.
Invitations to submit an article by clicking the link provided, and without stating the article processing charge (APC). Predatory journals may charge over $3,000 to publish an article, but they do not give this information in their email invitation.
No link to a website.
Incomplete contact information.
An address found in the email is for a home or some other non-office location.
Many (though not all) predatory journals can be found in original Beall’s List of Predatory Journals and Publishers. Bear in mind Beall's List has been accused of being sometimes too aggressive in its selection and targeting journals coming from developing nations. You can use the list as a guidepost, but also do your due diligence using tools like Think, Check, Submit.
After searching in PubMed, look to the left of your search results for the heading named My Custom Filters. Keep scrolling until you see Additional Filters. Click Additional Filters.
Scroll to Other. Then, check off Medline:
Medline-indexed journals have a much stricter vetting process, and it's highly unlikely that a journal that has been selected for Medline is predatory.
To check if an individual journal has been indexed for Medline, type the name of the journal into this search engine. Locate the journal in the list. There will be a filter on the left hand side of the screen that says Journals currently indexed in MEDLINE. Click that and see if the journal disappears:
The websites of predatory journals and predatory publishers list misleading, fraudulent, and fake metrics.
Before trusting a journal/publisher website's claim regarding its impact factor, find out for yourself from a trusted source. Journal Citation Reports is one such source you can use to obtain the impact factor for a journal. You can Ask Us! to search Journal Citation Reports for you; or, if you have Harvard access, you could also do your own search.
COPE (Committee on Publication Ethics) discusses a case where an author seeks withdrawal of an accepted manuscript from a predatory journal.
Attorney Sara F. Hawkin's blog offers advice on when and how to file a DCMA (Digital Millennium Copyright Act) Takedown Notice, and also a sample DCMA takedown notice template.
It is usually best NOT to do so, since doing so only enables predatory cycle and lends legitimacy to the predatory journal. However, it is a difficult decision and one that can be made only by very close, critical reading of the article. Authors of systematic reviews should be careful not to cite articles from predatory journals.
Invitations to present at predatory conferences can be identified through many of the same telltale signs as invitations to submit to predatory journals. Names of predatory conferences may vary in only the most minute detail from legitimate conferences from those of legitimate conferences. Read more about predatory conferences.
NIH's statement:
Selected articles: