APA parenthetical citation: is extra information in the parentheses okay?

Question

I'm proofing a document that employs the APA citation style. It contains several citations of the form:

(Michaelson, 2000; cattle only)

This seems wrong to me, especially since the semi-colon is used to separate references. However, I can't find anything in the Sixth Edition that gives me any guidance one way or another.

Personally, I would either put the "cattle only" bit in square brackets, e.g.

(Michaelson, 2000 [cattle only])

or rewrite to cite non-parenthetically, e.g.:

"... as was also noted by Michaelson (2000), but for cattle only."

I'd prefer to go to the client with more than "I don't think you should do this because it violates my sense of aesthetics".

Does the APA Sixth Edition give any guidance on how extra information should be displayed?

Answer 1

APA Style does not allow for additional information within citations. That is properly the function of footnotes or content notes and APA Style does provide for these. See The Purdue Owl website for more details. This site has been my go-to for APA formatting for several years now.

Note: According to the Purdue Owl website linked above, APA Style has historically discouraged the use of footnotes and content notes due to costs to publishers in regard to typesetting. I believe modern digital production methods have largely eliminated these concerns.