If possible, could you cite the article it was used in? Also if there is an Cronbach's Alpha and Factor Analysis available, that would be very helpful!
Robert Cialdini is the king of Persuasion and Influence. I can't think of a specific article or book of his to point you to, but I'd bet that his research has the scale that you're looking for.
Hi Jeffrey, thanks for your answer. I actually did read some work of him, just didn't realize it before! The reason I asked this question (and I'm still not satisfied even though you helped me a lot by giving me more for a good theoretical framework: I agree that he is the founding father - together with Petty and Cacioppo - of Persuasive Intent. Cialdini's insight is very theoretical. His measures - or at least the arguments why he used these measures - are somewhat lacking in my opinion.
He, Petty and Cacioppo use single item measures that are adopted throughout dozens of studies and are still used in some form today. Some studies take his exact words, others alter them in a way that fits their research better. Not only causes this inconsistency issues throughout findings in literature, it also makes studies almost incomparable theoretically. In addition, I tend to be distrustful of social constructs measured in single items, since social constructs are usually very nuanced, delicate and complex, something like 'persuasive intent' is unlikely to be fully captured by a single question.
I was (and still am) hoping to find (or be handed) a multilevel scale that has been properly and thoroughly, statistically tested.
You can maybe look at the article by Chang-Dae Hama, Michelle R. Nelsona & Susmita Dasa on "How to Measure Persuasion Knowledge". They present a literature review in terms of measurement and methods.