He may lean democrat, but I do think that his statistical analysis company and their results matter to him, so he tries to get it right.
He did. But not by much. per wiki...
On September 3, 2014, FiveThirtyEight introduced its forecasts for each of the 36 U.S. Senate elections being contested that year.[538 82] At that time, the Republican Party was given a 64 percent chance of holding a majority of the seats in the Senate after the election. However, FiveThirtyEight editor Nate Silver also remarked, "An equally important theme is the high degree of uncertainty around that outcome. A large number of states remain competitive, and Democrats could easily retain the Senate".[538 83] About two weeks later, the forecast showed the Republican chances of holding the majority down to 55 percent.[538 84]