Nate Silver vs. Sam Wang

In 2012, as I remember, Silver and Wang’s election forecasts remained close to each other. But right now they are considerably apart. Silver says Republicans have a 63.8 percent chance of winning a majority. Wu says Dems have a 79 percent chance of keeping the Senate.

Where do they differ? Silver thinks Pat Roberts of Kansas will keep his Senate seat; Wu does not. The pair of prognosticators also split over North Carolina. They must disagree on some other races but I cannot tell which ones.