This is interesting, but it lacks analytical rigor. Fortunately, I have done an analysis on a similar group of politifact subjects, specifically those would-be candidates for the US Presidency as of January, 2016 (plus Mr. Obama and Ms. Pelosi as reference points). My analysis does not grossly contradict the chart, but it does provide context and somewhat more rigorous clustering of the individuals in question. It can be found at http://nerdypolitical.blogspot.com/2016/01/presidential-candidates-politifact-and.html
I hope people take a look and get some value from it.