Sometimes called low-quality publishers, these companies use a variety of means to persuade or extort authors to publish in their journals, but they are not reputable, tend to have below average citation rates and contribute little to overall science. You should avoid publishing with them, but the number of predatory publishers and their techniques can be difficult to navigate.
Center for Open Science definition: “Predatory journals and publishers are entities that prioritize self-interest at the expense of scholarship and are characterized by false or misleading information, deviation from best editorial and publication practices, a lack of transparency, and/or the use of aggressive and indiscriminate solicitation practices.”
Journal title or publisher is unfamiliar
Lures you in with a very good sounding offer
Journal title sounds very respectable
Article submission costs are not transparent
Uses address in prominent city
Editorial board claims prominent university affiliation
Review system is unclear
Journal title not present in Directory of Open Access Journals or other indexes commonly used
Publisher should be listed in one or more directories for ethical publishers