Princeton Election Consortium

A first draft of electoral history. Since 2004

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 →]

→ 14 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

Pardon our mess…

June 9th, 2016, 4:23am by Sam Wang

A fair amount of construction is going on around here. There may be a few bumps along the way. For example, right now we’re tweaking the banner (until now it was updated manually).

Starting this summer, I am on the lookout for a new partner in running PEC, as Mark Tengi moves on from Princeton. Ideally, the person is part of the Princeton community (student or otherwise) and conversant or willing in Python, WordPress backend, and Linux. Write me!

→ 34 CommentsTags: 2016 Election

The Second Phase of Realignment: 1976-2012

June 5th, 2016, 12:00pm by Sam Wang

Shifts in American political geography (“realignments”), which I wrote about on Thursday, can be viewed at a glance using the following diagram. It allows us to see just how little change there has been in recent years – including 2016 so far. [Read more →]

→ 48 CommentsTags: 2004 Election · 2008 Election · 2012 Election · 2016 Election · President

The Realignment Myth

June 2nd, 2016, 3:35am by Sam Wang

With a candidate as strange as Donald Trump, it is tempting to speculate that the usual red-state and blue-state assignments may not hold. Trump is probably not a leader of change in the Republican Party, but rather the visible manifestation of a realignment within the party that has been brewing for years. Will national voting patterns change too? [Read more →]

→ 18 CommentsTags: 2004 Election · 2008 Election · 2012 Election · 2016 Election · President

State-poll snapshot: Clinton 336, Trump 202 EV; Meta-Margin +4.2%

May 31st, 2016, 10:32am by Sam Wang

Thanks to Brad DeLong, who has collected some of my oldies from January 2016. Back then, I outlined how polling data and Republican party rules pointed clearly toward a Trump nomination.

Here at PEC we are ramping up slowly. In the top banner is a preview of the main product: a snapshot of state polls. It’s basically the same as previous years, a day-to-day snapshot of state polls for the general election. This year, I am also adding a November prediction.

Brief notes: [

→ 62 CommentsTags: 2016 Election · President

Nomination rules and November nerdery at the NYT

May 25th, 2016, 9:57am by Sam Wang

In the New York Times, an article about the Republican Party considering changes to its nomination rules process to eliminate “chaos,” which I think is a code word for “Trump.” However, my quick scan does not reveal any proposed changes that would solve their Trump problem. As I wrote last July in The New Republic, some kind of instant-runoff or ranked-preference voting might have gotten them out of their current jam. Probably that’s too fancy for them to consider.

Also, I see The Upshot is drilling into the Erikson and Wlezien data that I used for the post below about November predictions. They only use data from 1980, but their answer appears to be similar to mine – except that I added a predictive calculation based on the data. Again, that’s just my quick scan of it.

→ 31 CommentsTags: 2016 Election · President