QUOTE(Malleus @ Sat 26th November 2011, 1:28pm)
You still don't seem to have quite got it. How are you defining collaborators?
According to the study, the information on collaborators is drawn from "Source WP:BFAN, counting collaborations with full credit"
I don't know where that page is. Can't find it, so can't evaluate it.
I checked some individual FAs mentioned. Especially if the article was on an obscure topic, usually the FA editor either originated the article, or contributed the overwhelming number of edits. In a block buster such as Parkinson's disease, the editor contributed over 900 edits with the next-in-line editor contributing 200. The first editor also took the article through GA and a couple of FACs.