Here at FiveThirtyEight, we’ve never built a complete back-to-front model of the presidential primaries before. Instead, in 2008, 2012 and 2016, we issued forecasts of individual primaries and caucuses on piecemeal basis, using polls and demographics. We always thought there were too many complexities involved — how the outcome in one state can affect the next one, for example — to build a full-fledged primary model.
But this year, we’re giving it a shot. CONT.
Nate Silver, FiveThirtyEight