Though multiple definitions of predatory journal exist, a predatory journal can be succinctly described as "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.”
Illustration by David Parkins, used with permission. Quote and image source: Grudniewicz, A., Moher, D., Cobey, K. D., Bryson, G. L., Cukier, S., Allen, K., … Lalu, M. M. (2019). Predatory journals: No definition, no defence. Nature, 576, 210–212. https://doi.org/10.1038/d41586-019-03759-y
Using the label "predatory" for a publisher or journal is sometimes controversial. For example, while journals from less developed countries may have less stringent practices, some believe they may also serve a role in forwarding scholarship in that country. Unfortunately, there is no one authoritative "list to rule them all." While these lists may be helpful, ultimately you should decide for yourself whether you believe a publisher is predatory using the criteria on this guide. To fully inform your decision, here are lists of journals that others have deemed predatory, and those deemed to be quality.
Image Source: Sax, P. E. (May 18, 2018). Predatory Journals Are Such a Big Problem It’s Not Even Funny [Blog Post]. Retrieved from https://blogs.jwatch.org/hiv-id-observations/index.php/predatory-journals-big-problem-not-even-funny/2018/05/28/
The following lists are adapted from academic journal articles that discuss how to identify predatory journals. If a journal meets a few of these criteria, that does not necessarily prove it is predatory, but it does mean you should closely scrutinize the journal for more red flags.
Source: Shamseer, L., Moher, D., Maduekwe, O., Turner, L., Barbour, V., Burch, R., Clark, J., Galipeau, J., Roberts, J., & Shea, B. J. (2017). Potential predatory and legitimate biomedical journals: can you tell the difference? A cross-sectional comparison. BMC Medicine, 15, 1–14. https://doi.org/10.1186/s12916-017-0785-9
Source: Eriksson, S., & Helgesson, G. (2017). The false academy: predatory publishing in science and bioethics. Medicine, Health Care, And Philosophy, 20(2), 163–170. https://doi.org/10.1007/s11019-016-9740-3