All the evidence you have given so far is in no way verifiable and relies solely on eye witnesses, which is the worst sort of evidence you could ever hope to use. (religion.blogs.cnn.com)
Finally, a different but quite compelling sort of evidence about leadership effects derives from research on leadership succession. (wallacefoundation.org)
Combining testimony and various other sorts of evidence requires mapping out a network of interrelated probabilities; the math quickly can become much too complicated for pencil and paper — and, until relatively recently, even for computers. (sciencenews.org)