How much trouble will Hillary Clinton be in if she loses in Nevada, where Democrats will caucus on Saturday? How close does Bernie Sanders need to come in South Carolina, which votes a week later? And which states are really “must-wins” for Sanders in March, April and beyond?

We can try to answer all of those questions with the help of the gigantic chart you’ll see below. On the left-hand side of the chart, you’ll find a projection for how each state might go if recent national polls are right, with Clinton ahead of Sanders by about 12 percentage points nationally. The right-hand side is more crucial: It shows how the states might line up if the vote were split 50-50 nationally. Since the Democrats’ delegate allocation is highly proportional to the vote in each state, that means Sanders will be on track to win the nomination if he consistently beats these 50-50 benchmarks. Conversely, Clinton will very probably win the nomination if Sanders fails to do so, especially since superdelegates would likely tip a nearly tied race toward Clinton.

The starting point for these estimates is state-by-state polling from Morning Consult, a non-partisan polling and media firm that has surveyed about 8,000 Democrats online since Jan. 1. That’s a lot of responses, although not enough to provide an adequate sample size for all 50 states; while there are about 800 respondents from California in the sample, for instance, there are only a dozen or so from Montana.

The solution is to blend the polling results with other data. In particular, I used exit polls to determine the nonwhite share of the Democratic electorate in each state and how each state lines up on a liberal-conservative scale (Sanders does better in white and liberal states). I also included the amount of money raised by Clinton and Sanders in each state in individual, itemized contributions, and their ratio of Facebook likes. In states like California where there’s an adequate sample size from the Morning Consult polling, the polling gets a fair amount of weight, but in the smaller states the other factors predominante. (For a more technical explanation of how this is accomplished, check out the footnotes.1)

http://fivethirtyeight.com/features/bernie-sanderss-path-to-the-nomination/