Nate Silver

Live Polls And non-Live Polls yield different results

With a backdrop of companies struggling to get both consistent and credible polling, it is interesting to analyse how different polling methods can skew the answers.

FiveThirtyEight generally takes an inclusive attitude towards polls. Our forecast models include polls from pollsters who use traditional methods, i.e., live interviewers. And we include surveys conducted with less tested techniques, such as interactive voice response (or “robopolls”) and online panels. We don’t treat all polls equally — our models account for the methodological quality and past accuracy of each pollster — but we’ll take all the data we can get.

This split, however, between live-interview polls and everything else, is something we keep our eye on. When we launched our general election forecasts in late June, there wasn’t a big difference in the results we were getting from polls using traditional methodologies and polls using newer techniques. Now, it’s pretty clear that Hillary Clinton’s lead over Donald Trump is wider in live-telephone surveys than it is in nonlive surveys.

We don’t know exactly why live-interview polls are getting different results than other types of surveys; there are a lot of potential causes and it’s something we’ll be digging into.

Online polling will become preferred due to the relatively low cost.  But unless the results are of a reasonable quality, live interview polls will remain the more credible.  We saw this recently when some rag commissioned a poll by a never-before-heard-of US company who had never polled on politics New Zealand previously.  The results were ridiculous.  Read more »

Which pollsters can you trust, and which are bought and paid for?

We should have something like this here.

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In the process of being an analyser of polls, Nate Silver has had to figure out which are actually delivering reliable and honest results, and which are essentially fronts that get you the answer you’re paying for.

We know that Colmar Brunton are one of the most variable and have a clear bias towards Labour, for example.

As for Horizon, they had the Conservative party in government as part of the coalition with National right now.

Whenever the Fraser House spy tells me that Labour are polling in the low to mid-thirties, and then paid-for polls come out, you can reliably subtract 4-6 points, every time.

 

– 538

Traditional political models predict Trump will absolutely tank

As an analyst of US politics, Nate Silver has been uncannily accurate and able to embarrass the pros.

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Nate Silver on why Republicans backed Trump

Nate Silver writes about the Trump phenomenon.

It is a great article from a writer who is the best predictor in politics.

If you’d told me a year ago that Trump would be the nominee, I’d have thought you were nuts. Don’t just take my word for it: Read what I wrote about Trump in July or August or even in November. Those pieces variously treated Trump’s nomination as being somewhere between improbable and extremely unlikely. You can also read pieces from October, December orJanuary that were less skeptical of Trump’s chances and show how our opinion of him evolved over time. Still, other than being early skeptics of Jeb Bush, we basically got the Republican race wrong.

Nice to see a pundit admit he was wrong. But how did he go wrong?

For a candidate like Trump to win the nomination, it means that several things have gone wrong — both for the Republican Party and in the assumptions we made about how party nominations work. The other day, I summed up the three most important such factors as follows:

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Trump now has a path to victory ahead of the convention

Yesterday Donald Trump cleaned out 5 state primaries and pretty much hoovered up all available delegates.

He now sits on 950 delegates, just 287 short of the required 1237.

Nate Silver now has him ahead of predictions and now in with a shot of making the 1237 threshold:

Tuesday night went about as well as possible for Donald Trump.

Two weeks ago, after a rough stretch of states for Trump, we issued a series of delegate projections that included something called a “path-to-1,237” projection, a set of targets that would allow Trump to clinch a delegate majority without having to rely on uncommitted delegates. With Trump’s terrific results in New York last week and even better ones in the five states that voted on Tuesday, Trump is actually running a little ahead of the path-to-1,237.

Based on provisional results, it looks as though Trump will sweep every pledged delegate in Maryland (as a result of winning every congressional district), Connecticut (as a result of winning every congressional district and getting more than 50 percent of the vote statewide), Pennsylvania (where statewide delegates are awarded winner-take-all) and Delaware (ditto), along with 11 of 19 delegates in Rhode Island (which is highly proportional). Combined with the New York results,2 that gives Trump 200 delegates since we issued the path-to-1,237 projections, five delegates ahead of his original targets.

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Trump will need to win on first ballot

If the Republican nomination fails to reach the threshold for delegates before the convention then it will become a contested convention.

If that happens, and there is a good chance that it will then Donald Trump will need to win on the first ballot.

Nate Silver at FiveThirtyEight explains:

If you really think the chance of a multi-ballot convention is 63 percent, but also still have Trump with a 56 percent chance of winning the nomination, that implies there’s a fairly good chance that Trump will win if voting goes beyond the first ballot. That’s probably wrong. If Trump doesn’t win on the first ballot, he’s probably screwed.

The basic reason is simple. Most of the 2,472 delegates with a vote in Cleveland probably aren’t going to like Trump.

Let’s back up a bit. In most of our discussions about delegates here at FiveThirtyEight, we treat them as though they’re some sort of statistical unit. We might say a candidate “racked up 44 delegates” in the same way we’d say Steph Curry scored 44 points. But those delegates aren’t just a scoring mechanism: Delegates are people, my friends. Delegates are people!

And as I said, they’re mostly people who aren’t going to like Trump, at least if the excellent reporting from Politico and other news organizations is right. (If Trump turns out to have more support among GOP delegates than this reporting suggests, even marginally, that could end up mattering a great deal.) How can that be? In most states, the process to select the men and women who will serve as delegates is separate from presidential balloting. In Massachusetts, for instance, Trump won 49 percent of the GOP vote on March 1 — his highest share in any state to date — to earn 22 of the state’s 42 delegates. But the people who will serve as delegates haven’t been chosen yet. That will happen at a series of congressional district conventions later this month and then a Republican state meeting in May or June. According to Politico, most of those delegates are liable to favor Ted Cruz or John Kasich rather than Trump. Twenty-two of them will still be bound to Trump on the first ballot, but they can switch after that. The same story holds in a lot of other states: in Georgia, Louisiana and South Carolina, for instance — also states that Trump won.   Read more »

Hacking the system: how Trump took the lead

Nate Silver writes at FiveThirtryEight about how Trump hacked the system.

As is usual with Nate Silver there is plenty of data and explanations before he gets to his conclusions:

Most of the media’s self-criticism of its Trump coverage has focused on whether Trump’s dominance of the news cycle reflects a craven desire for higher TV ratings or Web traffic numbers. It’s fine to debate that — although these criticisms are sometimes being evinced through crocodile tears given the record ratings and traffic Trump is bringing to news organizations of all kinds.12

But this critique avoids some thornier questions. For instance, with his ability to make news any time he wants with a tweet, news conference or conveniently placed leak, Trump has challenged news organizations’ editorial prerogative. Should the press cover a candidate differently when he makes trolling the media an explicit part of his strategy, on the theory that some coverage is almost always better than none?    Read more »

Trump’s path to victory

There are a great many people speculating on how Donald Trump can win.

I prefer data, which is why I read FiveThirtyEight for my information. Subscribers to INCITE: Politics will know that I recommend this site to everyone interested in knowing what is going on in US politics.

They explore the path to victory for Donald Trump, or at least get close enough to make a claim for him to be the candidate.

Some of their key points are:

harry (Harry Enten, senior political writer): My biggest takeaway is how on the knife’s edge this is going to be. We probably won’t know whether Trump is going to clear the 1,237 threshold until at least June. It’s March 21 — we have a long way to go.

dave (David Wasserman, House editor at the Cook Political Report and FiveThirtyEight contributor): First off, while we don’t know whether Trump will hit 1,237 or not, we should all be able to agree on one takeaway: For the first time in a very long time, every state will matter — and yeah, this thing’s going all the way to June. I don’t see any way for Trump to attain 1,237 untilJune 7, and I don’t see any realistic way for him to be mathematically eliminated from 1,237 before June 7.

natesilver (Nate Silver, editor in chief): When I was filling out my projections, I was a little bit surprised that I had Trump coming up short of 1,237 since I thought I was being fairly optimistic for him in individual states. However, once you account for the facts that (1) there are quite a few uncommitted delegates and (2) Trump isn’t likely to do so well in less populous states west of the Mississippi, which is a fair bit of what’s out there — well then, Trump has to do really well everywhere else.

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Is Sanders really ahead of Clinton?

There are many pundits, from the left-wing, crowing that Bernie Sanders is surging in the polls and has passed Hillary Clinton.

Apparently the donations have surged for Sanders after the news of the polls and Hillary Clinton attacking him for his donations.

But is he really in front? Let’s see what Nate Silver has to say. Remember, in last month’s INCITE:Politics we recommended his website for looking at the statistical analysis and probabilities of polling versus the guesses of the pundits.

First, you need to understand his methodology.

We launched our forecasts for the Iowa caucuses and New Hampshire primaries today. For much more detail about how this all works, you can read here. But our premise is that, given the challenges inherent in predicting the primaries, we’ll be publishing two models instead of pretending we’ve found a magic bullet:

  • The first model, which we call polls-only, is based only on polls from one particular state. (Iowa polls in the case of Iowa, for example.) It’s basically an updated version of the model we used for the primariesfour years ago.
  • The second model, polls-plus, also considers endorsements and national polls, in addition to state polls, and tries to consider the effect that Iowa and New Hampshire could have on subsequent state contests. (National polls aren’t necessarily a positive for a candidate in the polls-plus model; instead, it’s a bearish indicator when a candidate’s state polls trail his national numbers.)

Historically, polls-plus would have been somewhat more accurate, but it’s pretty close — so we think the models are most useful when looked at together.

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Fear and loathing in the media

Andrew Sullivan blogs about the knives shoved into Nate Silver’s back and why.

The part that resonates strongly with me is this:

[F]ear that his analysis could render moot some of the horse-race journalism that the NYT still does and does well. It’s a misplaced fear. Campaigns are narratives driven by human beings – no statistical analysis could begin to describe them adequately. There’s no reason the two approaches cannot work together and inform each other. But the pretensions and defensiveness of the old media guard seem to have made that a tough compromise to settle on – to the detriment of NYT readers.  Read more »