What share of the Hispanic vote do Republicans need to win in 2016? Is it 44 percent, as some have argued? Is it 49 percent? Or maybe it is as low as 33 percent?
If you’ve followed debates about elections for the past few years, you’ve probably heard analysts give answers to these questions. But the truth is, none of these answers are clearly correct. The reasons are threefold: First, these sorts of projections often hold all else equal from 2012 – that is, they assume that the white, black and Asian vote shares won’t move. Second, the projections offered typically involve the shares of the Hispanic vote (or that of other groups) that Republicans would need to win in order to take the popular vote. But, of course, our elections are determined by the Electoral College, and as we’ll see, Hispanic voters are much less relevant for the Electoral College than the popular vote.
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Because of this, we envision this as more of a heuristic device than a literal tool. In other words, if you put in an outcome and the Democrats win the Electoral College, but that win is dependent upon a state where the Democrat wins by 0.1 percent, you shouldn’t become convinced that Democrats would actually win with the outcome that you input.
Second – and this gets into our explanation of how the model works – we assume “uniform swing” across states. In other words, if the non-Hispanic white share of the electorate increases in the model by a point, it does so in every state. In reality, however, these swings will likely not be uniform. While we have some ideas about where the white vote might improve more for Republicans than the national margin would indicate (Iowa, for example), as well as for Democrats (perhaps Arkansas, if Hillary Clinton is the nominee), there’s simply no way to incorporate that objectively into a model.