The race has been stable for weeks, varying only by factors that are local to each state. Last night’s voting confirmed that – there was nothing new revealed. In terms of voter sentiment, the GOP race has been essentially unchanged since March.

How do we know this? Two reasons. The first is that national polls have been stable for four weeks, since March 22. The second is the remarkable success of a predictive method based on Google Correlate, which relies solely on past voting and web search patterns – and does not use polls or demographics at all. Here is how PEC and N.‘s Google Correlate method did (click to enlarge):

PEC, using a simple approach based on polls and border counties, did well. So did Google Correlate, when its results were fed through the delegate rules process.

Even more remarkable is the Google Correlate-based estimate of vote share. The chart below uses Google Correlate-based predictions (“Google-Wide Association Study” results) based on data excluding the candidates’ home states, and combines both Democratic and Republican primaries:

I’ll update this as more information becomes available, especially if I can find demographics-based predictions. At this moment, the closest thing I have is “538 demo,” which indicates an early estimate made by FiveThirtyEight assuming some kind of state-by-state constant shift. Google Correlate did notably better.

The “media data pundit” state-of-the-art is is demographics, which can give some predictive information, for instance in this year’s Democratic nomination. However, this year’s multicandidate Republican race has seemingly not lent itself well to such an approach. Demographic variables like %evangelicals are crude proxies for voter preference. Amazingly, Google search terms like “DeGrassi season 13” do much better. A future challenge is to understand why.

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In today’s PEC update, Trump’s median projected delegate count is 1308 (interquartile range 1281-1330), with a 94% probability of getting to 1237. The histogram looks like this:

The pre-East Coast primary delegate estimate was 1303 (IQR 1271-1326, probability 90%). The main effect of yesterday’s voting was to reduce uncertainty. I think it is reasonable to say that yesterday’s voting ended any realistic doubts about Trump being the eventual nominee. That is on a par with previous Republican nomination races: Romney and McCain were considered by their party to become the presumptive nominee in late April.

Since Google Correlate estimates larger margins than PEC does, it should give even less uncertainty. To demonstrate that, I have fed Google Correlate-based vote estimates into the PEC delegate estimator. Trump’s median projected delegate count then becomes 1334 (interquartile range 1306-1341), with a 99.6% probability of getting to 1237. The Google Correlate-based histogram looks like this:

I had briefly considered switching to Google Correlate-based estimates as the official PEC estimate. However, that approach does have a latent assumption that whatever new voting comes in is enough to capture any swings in the race. Before I take any such step, I have to think about the implications of that. Though come to think of it, polls have the same problem – less so in frequently-polled states, more so in rarely-polled states.

Update, 9:00pm: New poll medians/boundary-based estimates and Google Correlate predictions are here.