How Nate Silver Missed Donald Trump

[Lurker]

Putting up hypotheses based on data and testing them isn't "wrong".

Since polls are generally very unreliable in primaries compared to general elections, trying to put in more data makes sense.

But I guess joining the latest lynch mob to shout in unison is more fun for some people.

Well, he has seemed awfully certain about this, showing little indications of considering arguments that ran counter to his conclusions (and making a lot of dubious arguments himself, such as the idea that Trump as a candidate was more or less equivalent to earlier "anti-establishment candidates" (none of whom shared Trump's level of support over time, his celebrity status, and probably lots of other factors). Now that Silver is starting to backtrack, at the very last moment, I hardly think he should be considered the victim of a "lynch mob".

Sure, he may get a lot of unfair criticism, but on the flipside: When he's right, he is lauded as a genius, even when his statistical modeling barely differs from a simple polling average.

[Lurker]

@Figs: Here ya go.

That's interesting and goes part of the way toward what I was wondering, but it also doesn't necessarily give me an indication of whether endorsements as a variable is separable from polling support. He sketches a very, very rough idea of how endorsements might translate to votes, but I still don't have a good handle on exactly how much that effect might be captured by, or duplicating, other data.

I'm struck in particular by the Democratic charts for 2004. Kerry's endorsements spiked after he started succeeding in primaries, before which point they were lagging Dean and even Gephardt.

You're right that he doesn't show it's an independent variable that's discretely influencing outcomes -- but if it's a leading indicator, it seems like it's reasonable to model.  If you look at 2004, it strikes me that several candidates had comparable establishment support and the establishment started coalescing around Kerry, and then he continued to grow momentum.  It's true that elite endorsements weren't as much as a leading indicator there, since the establishment appears to have stayed out early on, but once they started to get behind Kerry, his momentum did continue and accelerate. And he was never really disfavored the way Trump (and Cruz, for that matter) is.  Kerry isn't much of a knock on the model, IMO.

But isn't this (similarly to Obama's increasing number of endorsements in '08) more a case of "the establishment" backing Kerry since he had gained momentum and appearing increasingly likely to win, rather than the endorsements causing him to win the nomination?  The same seemingly applies to 1988 as well (in which both Gephardt and Gore had more endorsement points than Dukakis shortly before Iowa).  

That's arguably at least three cases where the endorsements doesn't seem to have been such a significant factor, out of a total of six contested Democratic nominations.