Is APA-certified editor an actual credential?
If yes, is there a universally-accepted proof in the U.S. for that credential?
I tried a web search on "how to become an APA-certified editor." I clicked through four pages of the hits where the bulk of the references were about obtaining PhDs or APA licensing.
The hits I did find were for a few people advertising their services for APA-style editing, and one reference to an APA editing workshop.
I'm interested in (maybe) editing dissertations for doctoral students at small for-profit universities (not editing journals).