The answer is quite conclusive: ‘The accompanying graph represents the novel on the x-axis, broken into segments: the thicker the bottom line, the more certain the proximity to the relevant author’s style. Considering Patterson’s fingerprint is represented by green, it is plain to see that, contrary to our previous study, this is a co-authored novel in which he was the scribe.’
Of course, as O’Sullivan points out himself, we need to stay wary where the genre signal comes in to make life complicated (no fictional writing of Clinton’s could be used for the study, simply because there isn’t any). However, there is good reason to assume that the authorial signal here trumps the genre signal.
Finally, O’Sullivan points out another important dimension of that particular collaboration: that of the market. “What better way to sell a book, than to have a mogul of commuter fiction combine with a former US president?”
Interestingly, according to both Lane and O’Sullivan, it is the former US president who does raise his voice towards the end of the novel, contributing a finishing touch, or rather, a finishing strike to the tale:
“…there’s the chutzpah with which Clinton (Patterson, I would suggest, may have stepped aside at this stage) waits until the twilight of the novel and then, like Tolstoy, squares his shoulders and expounds, in fiction-free form, his politico-historical thoughts.” (Lane)
… and this is what it sounds like:
“I want the United States to be free and prosperous, peaceful and secure, and constantly improving for all generations to come.”
I’d like to conclude that the current state of world history is clearly up for political debate, while the novel is naturally subject of an aesthetic one. Meanwhile, O’Sullivan’s article is a great stylometry story – and we look foward to more of those.