Princeton Election Consortium

A first draft of electoral history. Since 2004

New York thread

April 19th, 2016, 10:16pm by Sam Wang


Trump heading for at least 90 out of 95 delegates. If his 60% vote share holds up, I’ll guess 92. Talk among yourselves…

Wednesday 7:30am update: for now, it looks like 90 delegates. Trump got below 50% in 3 districts, therefore losing three delegates. Kasich finished first in one district, leaving 1 delegate for Trump there. Overall, the average district vote share was 60.6% for Trump, with a standard deviation of 10.0% – a bit more than my assumption of 9%.

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GOP update, pre-New York

April 18th, 2016, 3:59pm by Sam Wang


Tomorrow New York votes. This is a critical race in the Republican primary campaign. Above is a final snapshot, based on polls and voting patterns to date. This calculation gives a median Trump outcome of 1265 pledged delegates (interquartile range or IQR, 1210 to 1305 delegates). The probability of getting 1237 or above is 64%. If polls are accurate, Donald Trump appears to be headed to getting 86 or more of New York’s 95 delegates.

The overall picture represents very little change from last week. Below are some technical notes, as well as state-by-state snapshots. I have updated my methods (details documented here). In the biggest new item, I show how to infer likely voting in states for which there are no polls, without use of any demographic assumptions. Using this method, I handicap Indiana as Trump +7%. [Read more →]

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“Momentum” and the Wannabe Physicists at Meet The Press

April 14th, 2016, 3:40pm by Sam Wang



In political reportage, the word “momentum” is nearly worthless. It gets used whenever a candidate wins a race or gets a favorable poll. As far as I can tell, a working definition of “momentum” is “I am excited about a noisy data point and will now give someone a lot of press coverage.” Remember John Dickerson and Ro-mentum? I guess discussing “momentum” levels the media playing field for trailing candidates, which is democratizing and maybe not all bad. Still, I cringe when the word is used.

Single primaries only tell what is special about that state. For example, on March 15th Governor John Kasich won his home state of Ohio. He went up in the polls – until March 22nd, when he lost Arizona and Utah, at which point his polling numbers peaked and started to come down.

Putting aside the incredible spectacle of the national Republican Party’s implosion, their nomination race has been remarkably uneventful in terms of voter sentiment. [Read more →]

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Current Polls Favor A Trump Delegate Majority

April 9th, 2016, 4:59pm by Sam Wang


This week in the Republican nomination race, Ted Cruz’s win in Wisconsin triggered buzz about how front-runner Donald Trump might be in trouble. Doubtless today’s win in Colorado will intensify the chatter, and will involve words like “momentum.” It is best to ignore all of that coverage – at least until some national polling data shows a sustained change. Why? Because states differ from one another, mostly in demographics but also in rules and various local factors. It is almost impossible to learn something new from a single race. To know where the race stands as a whole, it is necessary to consider all states at once.

In several ways, Wisconsin was typical. With a pre-election poll median of 36.0 ± 1.5% (median ± estimated SEM), Trump’s vote share of 35% was on the mark, continuing his close match between polls and outcomes. Cruz’s finish was also typical, but for a different reason: he was, and is, outperforming his polls. Cruz’s pre-election polls were 39.0 ± 1.2%, and he ended up with 48% of the vote. In previous states, Cruz has overperformed by a median factor of 1.2. Either Cruz’s supporters are exceptionally committed, or he is the beneficiary of anti-Trump votes liberated from their previous first choices, or undecided voters break hard for him, or some combination of the three. In Wisconsin he may also have benefited from the fact that trailing candidates like Kasich often underperform their polls when it is time to vote.

Where is the national race now? The current 6-national-poll median (March 29-April 6) is Trump 39.5 ± 1.2%, Cruz 31.0  ± 2.1%, Kasich 19.0 ± 1.1%. If we were to apply a 1.2-fold bonus to Cruz’s numbers to allow for his overperformance, the corrected numbers are Trump 39.5%, Cruz 37.2% – extremely close. Either way, Cruz has risen quite a bit in the last month, and national opinion is now closely divided.

I have updated the polls-only snapshot of the remaining Republican primaries through June 7th, when voting ends. As I pointed out months ago in The New Republic and The American Prospect, Republican rules are complex and tilt the playing field toward the front-runner, even if he/she doesn’t get a majority of the popular vote. Therefore it is essential to emulate the state-by-state delegate rules with close attention to quantitative accuracy.

Even after getting the rules right, this is a challenging calculation for three reasons: (a) many states lack polls; (b) Cruz overperforms his polls; and (c) delegates may not follow the rules. Today I describe one way of dealing with all of these issues.

For those who just want the bottom line: Since my last update, a poll-based snapshot has moved – in Trump’s favor. If current polls accurately measure voter behavior, then Donald Trump would get a median of 1,356 delegates – almost 120 more than the 1,237 he needs for a first-ballot victory at the national convention in Cleveland. For this probability to drop to 50%, his national lead would have to drop by 8.0% – this is Trump’s Meta-Margin, a measure I have previously developed for general-election Presidential races. However, if Cruz’s overperformance continues, Trump’s lead would narrow considerably, to a count of 1,280 delegates and a Meta-Margin of 2.0%. After allowing for Cruz’s potential overperformance, the probability of a Trump majority is 70% – probable but uncertain. Under such closely divided conditions, the outcome won’t be known until the last primaries, on June 7th.

And now I will explain at length. [Read more →]

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Princeton University: Woodrow Wilson report

April 4th, 2016, 10:03am by Sam Wang


Today, Princeton University releases its report on Woodrow Wilson’s legacy. You can read it here. Here’s the news release. One bottom line: the Woodrow Wilson school will retain its name.

My own view is that we as a community can’t run away from his segregationist views – nor would it be the best option to do so. [Read more →]

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High accuracy of aggregated Democratic polls

March 28th, 2016, 3:00pm by Sam Wang


Are Democratic primary polls accurate? In individual states they are good, with a few exceptions. At an aggregated level, they are remarkably accurate. The delegate-weighted polling margin has a total error of 3.1%. This is better accuracy than one would expect from the reputation of polling these days. The overall error is also not nearly enough to change my calculation from yesterday. [Read more →]

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No path for Sanders…but it’s a long one

March 26th, 2016, 11:55pm by Sam Wang


One thing Sanders understands well is the need for a horserace. Without that, he and his principal issue, economic inequality, won’t get covered.

It is possible to put a probability on the outcome that Sanders has outlined above: less than 5%. It’s also possible to calculate how long he can keep saying there’s a path: until June 7th. [Read more →]

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Slow news month ahead?

March 26th, 2016, 1:03pm by Sam Wang


I’m on a low-posting regimen for a little while. Basically, I think the Democratic and GOP primaries are settled.

That said, why don’t you comment on which of the following would be most interesting: [Read more →]

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Data scraping help (thank you!)

March 24th, 2016, 8:43pm by Sam Wang


Anyone care to help me extract some Wisconsin State Assembly results from this database? I am applying this proposed gerrymandering standard to this Common Cause challenge. [contact Sam] (Update: thanks to several readers, Steven Schuster from Colgate and Bror Jonsson here at Princeton, for the help. It’s under control!)

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John…you didn’t have to get me anything!

March 22nd, 2016, 9:22am by Sam Wang


See the updates. Trump and Cruz won Arizona and Utah outright. Overall, a subpar performance by Kasich. No gifts today.

Today, John Kasich potentially gives the first of a series of gifts to Donald Trump. What’s inside the box? Maybe 58 delegates – from Arizona, which is winner-take-all. [Read more →]

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