By how much will Clinton win?

American politics is great for statistics: there are huge amounts of polls being conducted every week, some positions are up for re-election every other year, and there is really only two parties. Moreover, the complicated nature of the whole election process, which for example involves the electoral college for the presidential election, makes it more interesting than most democracies around the world. It’s for all these reasons that an incredible website like FiveThirtyEight is possible.

I recently came across this interesting article from the Washington Post, claiming that demographics can not only predict the winner of each Democratic primary, but also the margin of victory. I reproduce their main figure below:

My first thought when I saw this graph was that we could actually make a prediction about when Clinton will most likely reach 2,383 delegates (which is how many she needs to win). But the delegate allocation process is quite complicated, and accounting for it in the prediction would be close to impossible.

Therefore, the next best thing is to look at exit polls from the 2008 democratic presidential primary and use this data to predict the results of tonight’s primaries: Michigan and Mississippi.

I took the results from the exit polls conducted by ABC, which tell us that about 50% and 23% of democratic voters are Black in Mississippi and Michigan, respectively. Therefore, the prediction goes as follows: