Princeton Election Consortium

A first draft of electoral history. Since 2004

Can Trump bring undecideds home?

July 7th, 2016, 9:05am by Sam Wang

July 20, 11:44pm: In light of tonight’s RNC speech by Ted Cruz, in which he pointedly did not endorse Donald Trump, it seems appropriate to revive this post from last week. Trump’s biggest deficit is lack of support from disaffected red-state Republicans. If they come back into the fold after tonight, it won’t be because of Ted Cruz.

As I wrote yesterday, there are more undecideds in the Clinton-Trump race than in the Obama-Romney race four years ago. The difference is 5.5 percentage points: in early July 2012, approximately 90.7 ± 1.1% (average ± SEM) of voters reported a preference for Obama or Romney. In 2016, total Clinton+Trump support is currently 85.2 ± 2.0%.

In practice, undecided voters tend to break approximately equally. However, these “extra undecideds” may not be the same as the run-of-the-mill voters who cannot yet express a preference to a pollster. Instead, Donald Trump is underperforming in a pattern that suggests that many Republicans in red states are disaffected by his candidacy. [Read more →]

→ 57 CommentsTags: 2016 Election · House · President


July 6th, 2016, 11:01am by Sam Wang

We are repairing a problem in our HuffPollster feed. We were not scraping states with few polls, and in those cases were using 2012 election results. This is now corrected. Current polls make the following states closer by at least three percentage points compared with 2012: AR, CO, CT, KS, ME, TN, TX, and WA. In addition, Nevada is now flipped to Trump +7% (one poll only). As a result, the EV estimator takes a jump today, as well as the Meta-Margin (from Clinton +3.9% to Clinton +3.3%). This is not a real jump, but a correction to make sure that all polls are included. I apologize for the error. (Update, July 8th: the history has been recalculated using the correct data. The jump is now gone.)

For those who are interested, code is here and daily output files are stored here. Documentation coming soon.

These corrections reflect a general phenomenon in which both parties’ candidates are underperforming compared to 2012, perhaps because of undecided voters. In early July 2012, approximately 90.7 +/- 1.1% (mean +/- SEM) of voters reported a preference for Obama or Romney. In 2016, total Clinton+Trump support is currently 85.2 +/- 2.0%. This year’s reduction in decided voters may reflect reduced enthusiasm for the candidates, particularly Donald Trump, who is notably weak in strongly Republican states. More on this later.

→ 9 CommentsTags: 2016 Election · President · Site News

Politics and Polls: a podcast with Julian Zelizer

July 1st, 2016, 12:00pm by Sam Wang

It’s a new collaboration with Julian Zelizer over in History. The first episode, produced by the Woodrow Wilson school, is posted here, as well as on iTunes. Topics include: is a 1964-like landslide possible this year? Does Brexit teach us anything about the Trump phenomenon? Does The Party Decide on nominees? Is a realignment of the two parties likely this year? (Spoiler: on all four questions, I am not bullish.) Take a listen!

→ 10 CommentsTags: 2016 Election · House · President · Senate

The Presidential Meta-Analysis for 2016

June 30th, 2016, 9:13am by Sam Wang

As we have done since 2004, we are taking a polls-only approach to give a daily snapshot of the race – as well as a November prediction. This approach has an effective precision of a few tenths of a percentage point of public opinion, and performs very well as both a tracker and a forecast. Currently, the probability of a Hillary Clinton victory in November is 85 percent, based on polls alone.

Today, I give a brief tour of the computational approach. [Read more →]

→ 49 CommentsTags: 2016 Election · President

Graph of the day

June 29th, 2016, 12:24pm by Sam Wang

On most news days this month, there has been some pointless story about a single poll. Journalists’ instincts to report on the exceptional event are totally inappropriate for following polls, where the median result is the one that is most likely to be true. After 12 years of poll aggregation, wouldn’t their profession have adopted better practices by now ? Anyway, Clinton has been up by 5 to 7 percentage points all month. There is nothing else to say about that. Also, we are starting to get state polls, which will fill in the picture considerably.

Meantime, this is of at least equal significance for November:

→ 46 CommentsTags: 2016 Election · President

An online app to diagnose partisan gerrymandering

June 26th, 2016, 11:30pm by Sam Wang

Today, Mark Tengi and I release an online application to help diagnose whether partisan gerrymandering is evident in a set of election results. The application is intended for the use of judges, clerks, litigants, and others who want a statistically well-founded and easily understood test for partisan asymmetry. The Supreme Court has suggested that partisan asymmetry may form a basis for a manageable standard for partisan gerrymandering, but they have not settled upon a specific standard. I hope to fill that gap.

The website,, implements three tests for partisan gerrymandering as described in an article I published last week in the Stanford Law Review. These proposed standards recently won a prize in Common Cause’s 2016 contest to define a partisan gerrymandering standard. The website is in beta-test, and I welcome your comments. If you detect a problem, email the output PDF if possible.

My three standards have two key features: (1) they implement the principle of partisan asymmetry, as others have also recently done; and (2) they do so without the use of any consideration of maps.

The second point is quite important. Most people who get exercised at the offense of gerrymandering may gravitate toward examination of a district’s convoluted boundaries. Although this is perfectly reasonable, existing precedents and consequences of the Voting Rights Act have conspired to make consideration of boundaries a tough sell with courts – at least for statewide partisan gerrymandering. Let me explain. [Read more →]

→ 21 CommentsTags: House · Redistricting

Brexit survey of the day

June 24th, 2016, 4:42am by Sam Wang

The UK voters who dominated the vote to Leave are also the ones who have to live with the outcome for the least amount of time.

And then there is this fascinating essay in Dissent magazine, which describes two Englands: elite England centered almost entirely in London, and excluded England composed of everyone else. Excluded England includes working classes, poor areas, former industrial districts – regions and classes that have not partaken in the reinvigoration that has been promised as part of membership in the European Union. All in all, they sound rather a lot like the pro-Trump wing of the Republican Party.

Finally, Paul Krugman ponders the aftermath of Brexit in a fairly non-panicked manner. He suggests that the problems in the European Union were there all along, and this vote changes nothing. He does suggest that the vote is pretty bad for Britain in the long run. They wanted to revive Britain; what they may get is a revived England (and probably Wales), severed from Scotland and Northern Ireland.

→ 31 CommentsTags: United Kingdom

Brexit polls microscopically favor Remain

June 23rd, 2016, 11:00am by Sam Wang

Today, the UK votes on a referendum on whether to Remain in the European Union, or to Leave. In polls started since June 16th, the current median is Remain +1.0 +/- 1.8% (n=7; median +/- estimated SEM; probability of a lead among decided respondents=70%). Where a single pollster conducted multiple polls in the last week, I used the most recent survey. So among decided respondents, Remain is very slightly ahead.

HuffPollster reports about 9% of respondents still remain Undecided, enough to swing the outcome either way. Where multiple polls were available from one pollster, the direction of change was YouGov 0.5% toward Remain, NBC/SurveyMonkey 4% toward Remain, and Survation 3% toward Leave. This is ambiguous.

Big referenda like this can contain hidden strains of opinion. For example, in 2014 the Scotland independence referendum failed by 6% more than indicated by polls. That was a situation of some voters being little-c conservative, in the sense of avoiding drastic change. Naively, I think such a dynamic would favor the Remain side…but we will see. Could still go the other way.

The Scotland failure led to stengthening of the SNP, with echoes felt in the UK today. Even if Remain wins, what will be the consequences of today’s vote?

Update, 8:54pm: “Leave” is doing better than expected in many constituencies. Follow the results at the Guardian’s liveblog and tracker.

Friday morning: I had a bit of trouble with updates last night, so couldn’t post this. An excellent projection was done by Chris Hanretty of the University of East Anglia. His interpolation made it clear by about 9:00pm Eastern (2:00am UK) last night that Leave would win.

→ 25 CommentsTags: United Kingdom

The Takeaway – today!

June 16th, 2016, 8:46am by Sam Wang

Today on The Takeaway, John Hockenberry and I discuss whether a realignment is brewing (spoiler: probably not). On WNYC-AM at 9:00am Eastern, WNYC-FM at 3pm. Broadcast nationwide, and here is the recorded podcast.

→ 27 CommentsTags: 2016 Election

How behavioral science could help get more Americans to vote

June 15th, 2016, 9:03am by Sam Wang

My latest, in the Washington Post.

→ 14 CommentsTags: Politics