I'm looking for some advice regarding a project idea I have. I would like to predict the big five personality traits for authors based on an analysis of their writing samples. However, would I need to have had some authors take the big five personality assessment and have a training set with those results in order to do a project like this? Or is their a way to "guess" what certain writing patterns would correlate with? What would be the potential strategy for orienting an ml project like this?