Political Scientist Ben Highton explains:
If the 2016 presidential vote is evenly split between the parties, which one is more likely to win the Electoral College and therefore the presidency? I estimate that the Democrats’ chances of winning the Electoral College vote are between 83 and 89 percent, giving them a significant advantage. This argument contrasts with those who are cautious of a Democratic advantage, such as Jonathan Bernstein and Harry Enten. The reason I predict such a significant advantage is because of ongoing, long-term trends altering the electoral outlook in a number of key swing states… (keep reading)
Highton offer a more technical explanation of his methodology here.