Surveys in defamation cases?

Eriq Gardner at THR Esq. rightly flags this tantalizing tidbit about Tom Cruise’s pending defamation lawsuit (okay, I have a very specific definition of tantalizing; don’t judge me).  Cruise conducted a survey to figure out how readers would interpret the claims at issue.  From the papers: 

Defendants are certainly free to argue that their cover headlines are mere 'opinions' of how Suri was feeling in the wake of her parents’ divorce. Plaintiff is likewise entitled to demonstrate that any reasonable reader would interpret Defendants’ headlines as conveying a verifiable statement of fact about Plaintiff’s conduct. Indeed, Plaintiff has already submitted survey evidence to Defendants showing that a majority of readers in fact interpreted the headlines 'Abandoned By Daddy' and 'Abandoned By Her Dad' as conveying the message that Plaintiff cut Suri out of his life altogether and on a permanent basis – i.e., that he had severed his relationship with her and they no longer had any contact whatsoever. Conversely, less than 4% of readers understood the covers to communicate anything about Suri’s feelings.

I've never heard of a survey in a defamation case before, but I suspect surveys in defamation cases will have the same problems of manipulability that they do in Lanham Act cases.  It’s an interesting (and likely expensive) development nonetheless.