Q. How can I tell whether or not a certain journal might be a predatory scam operation?

Deceptive, sham, and hoax publishing operations have become an unfortunate reality in online journal market. Some basic tips can help you avoid falling prey to their scheme.

Consider these questions:

 1.   "Where is this journal indexed?"

If the journal is indexed in MEDLINE, then this indicates that the title was carefully reviewed by committee to ensure that it met specific criteria indicating high professional and ethical standards. MEDLINE indexes about 6000 Biomedical & Health Science journals. The details can be found here.

To check on a specific journal, use this MEDLINE JOURNAL Search and query the title of the journal in question. 

https://www.ncbi.nlm.nih.gov/nlmcatalog?term=currentlyindexed

Remember it is only in this specific MEDLINE listing shows the journals that have been reviewed for their academic research integrity. 

If the journal is not indexed in MEDLINE, check to see if it is indexed in "Journal Citation Reports" within the Web Of Science. Here too, the journals included in WoS indexing have gone through a screening process:

http://nrs.harvard.edu/urn-3:hul.eresource:scicitin

"Journal Citation Reports" will be located at the very top navigation menu from the Web Of Science search screen.

2.    "Is the publisher a member within a trusted professional society or organization?"

Many legitimate Open Access publishers are taking steps to align themselves within trusted organizations like COPE and OASPA to ensure the academic community that they are adhering to the high academic standards that we need to maintain:

Committee on Publishing Ethics (COPE)

https://publicationethics.org 

Open Access Scholarly Publishers Association

https://oaspa.org

3.    "What are other academics saying about this journal/publisher?"

Unfortunately there is no "one simple list" that sorts out the "great journals" from the "sloppy journals" from the "absolutely fake 'journal'". Many have looked at Beale's list as a starting point, but there are indeed problems with relying solely on Beale's (too many to mention here... but provided for your reference).
 

https://beallslist.weebly.com/

Sometimes just hearing the comments, concerns and suspicions of your professional colleagues is good enough to make a sound judgment to publish elsewhere. My personal favorite of one such blog, where frequent observations and comments arise around predatory publishers is here:

http://flakyj.blogspot.com