Final Projections 2016

November 8, 2016 by Sam Wang

(Updates: 6:06am data for Presidential and Senate, and added confidence intervals. 9:00 am: more description, also variance minimization.)

Here are the final snapshots. Four Senate races are within one percentage point: Indiana, Missouri, New Hampshire, and North Carolina. Partisans there may want to lawyer up for possible recount battles.

Soon I’ll put out a brief Geek’s Guide to the Election. Also, live blogging starting around 8:00 pm.

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President: Hillary Clinton (D).

The Presidential estimates are based on the current snapshot in the right sidebar, except for the most-probable-single-outcome map, where variance minimization was done to give a more stable snapshot for North Carolina, Clinton +1.0 ± 1.0% (N=8 polls).

Most probable single outcome (shown on map below): Clinton 323 EV, Trump 215 EV. This is also the mode of the NC-adjusted histogram.

Median: Clinton 307 EV, Trump 231 EV. Meta-Margin: 2.2%. One-sigma range: Clinton 281-326 EV. The win probability is 93% using the revised assumption of polling error, +/- 1.1%.

(Why doesn’t this probability necessarily match the probability in the snapshot histogram?)

National popular vote: Clinton +4.0 ± 0.6%.

Senate

Where possible, variance minimization was used to identify a time window that gave lower variance than the standard time window.

Mode: 51 Democratic/Independent seats, 49 Republican seats; the most likely single combination is shown in the table below.

Median: 50 Democratic/Independent seats, 50 Republican seats. (average=50.4 ± 1.1 ; the 1-sigma range rounds to 49 to 51 seats)

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House

Generic Congressional ballot: Democratic +1%, about the same as 2012.

Cook Political Report-based expectation: 239 R, 196 D, an 8-seat gain for Democrats.

31 Comments

Walter Manny says:

Looking back at the Michigan primary polling error (http://election.princeton.edu/2016/03/09/how-surprising-was-the-sanders-win-in-michigan/) what do we make of the bad news on that side of the coin (MI, -19; AZ, -12; NC, -10; NH, -9; PA, -4; IA, -4)? The good news is: OH, +6; FL, +3. Hard to say about caucus states CO, NV. Forgive me if this ground has been covered, would love a link to it.

Deep breaths, deep breaths says:

Sam, some at Yale is talking smack about you!
https://www.quantamagazine.org/20161108-why-nate-silver-and-sam-wang-are-wrong/

Ed Wittens Cat says:

The King is dead…
Long live the King!
Nate is REALLY not gunna like this.

Ed Wittens Cat says:

from Wired article–
Because Wang has sailed True North all along, while Silver has been cautiously trying to tack his FiveThirtyEight data sailboat (weighted down with ESPN gold bars) through treacherous, Category-Five-level-hurricane headwinds in what has easily been the craziest presidential campaign in the modern political era.

Sam Wang says:

Hey, everyone – can you please not do a victory dance over this article? I would like to reduce this kind of comparison. You all know what he has done to create this activity in the public eye. He’s a pioneer.

Ed Wittens Cat says:

I told you in 2012 that i was done with Silver
when he disappeared the NYT piece he wrote debunking the dem oversampling myth.
That was pure unadulterated pandering.
Scientists and mathematicians have a deep responsibility to the public good….to not whore themselves out for clicks and eyeballs.
That is why transparency of poll aggregation models is so important.

David 3369 says:

Cat: regardless, it does not increase the net good in the world to stir up (or egg on) a cat fight. The world would be improved by reconciliation here.

Amitabh Lath says:

Has anyone else noted the fixed periodicity in the MM plot and those of other poll watchers like the Upshot? Peak-to-peak seems to be a little less than 2 months. Strange because the state plots (Upshot for instance) do not readily show this feature. But the national plot is a convolution of the state plots, so this is some emergent behavior.
Does anyone have FFT code? Be curious to see if this is telling us something.

Bob McConnaughey says:

Not FFT but i have some SAS code i can dig up that is set up to evaluate seasonality; actually it was borrowed from this site by Ed Stanek:
http://www.umass.edu/seasons/pdffiles/sea05d01.pdf
we converted the dates to Julian dates, obtaining the thetas in radians, getting the sin/cos of the radian measures, but it was really this guy’s SAS code.

Amitabh Lath says:

Pretty sure it’s going show to spike at k = 1/2months. But what does it mean? What happens on that timescale?

Shawn Huckaby says:

BTW, data is always beautiful, no matter what Wired says! 😉

gumnaam says:

Yes, that ‘godawful web design’ line in the article made me think: what are they talking about? That’s when I realized for the first time that I am a nerd.

Matt McIrvin says:

Old-fashioned web design. Which is not necessarily bad.

Joeff says:

Maybe this is covered down-thread, but how do you get 98-99% chance of HRC win if the left tail of the histogram is below 270? Do those only amount to 1-2% of total outcomes?

Scott H says:

discussed a bit below and other posts. Short answer: the PEC prediction does not use the histogram to make predictions. Just “what’s the odds that MM>0 on election day” where the MM is calculated only using the median of the histogram. Doesn’t change things much this election, but maybe something to think about in the future.

UI Supporter says:

Good interview on MSNBC. All good points were made.

Marv says:

Hi Sam, why did PEC’s final number of 323 EV for HRC drop this morning to 307? Did you put NC into the DJT column?

San Fran Sam says:

What do you want to bet that the Trumpster is going to whine and moan about a rigged election because he won just as many states as Clinton did?

James Orr says:

Every election the Democrats win I get post-election e-mail from a cousin that shows that the land area of districts won by the Republicans vastly exceeds the land area of districts won by Democrats, as if land, and not people, voted.

Sophia says:

Dr. Wang, I appreciate your steady, stable and classy demeanor during this whole election. Thank you for giving me a place to go to that is sane when it comes to politics. You do wonders for the psyche!

James Orr says:

Where’s the “Like” button?

Steven Rickard says:

Well, Sam, it looks like that tasty bug will have to wait at least 4 more years to be eaten! Well done sir!

John in LA says:

Is the map image wrong, or am I just seeing things? The stated EV Snapshot is Clinton-307, and yet the map shows Clinton-323, then links to a map showing 308.

Leading Edge Boomer says:

The page header differs from the “Final Projections.”

Graham Strouse says:

I think of the challenges to pollsters going forward is going to be trying to factor in externalities into the data. My father worked in surgery research for 30 years. When he started in the ’70s, a response rate of 80% was considered adequate. How it’s a bout a tenth of that. The increase in cell phone only households has increased by a staggering Volume just in the last 8-10 years. At this point if I was weighting polls, I doubt I would use any information more than 20 years old, and I would also probably try to factor in demographics more aggressively when weighting polls.

DeanH says:

Based on the map, Dems win 14 states with 10+ electorial votes to 7 states for the Repubs. Kind of tells it all. The problem for Dems in the House is it is easy for Rs to gerymander because of the big cities. They rip off pieces from the cities to make districts. SCOTUS could stop that and may in the next 2 years.

anonymous says:

I think the state that will be the canary in the coal mine is MI. Apparently, there is talk of T getting those white, blue collar voters there.

Dr Raucous Indignation says:

Dr Wang, you have been my rational safe harbor during the last year and a half. The work you do is important and very impressive. It helped inform me and shape where I sent my support. I will see you all too soon for 2018, ugh.

Ava de Cenizas says:

Dr. Wang,
You are a class act all around. I enjoy the wry tone of your posts and your refusal to heavily criticize other data analytics. We need more cool heads like you sir. I have enjoyed both you and Silver’s site as an attempt to apply rigorous analysis to a deeply emotional situation.

tudorguy says:

Alas, it seems the “rigorous analysis” has failed. Nate Silver’s model was more true, in that his acknowledged the uncertainty in the polls. Tomorrow Dr. Wang will engage in much verbal and statistical gymnastics to explain why he was wrong. But it is a bitter thing for those who relied upon his knowledge and skills. He is not to blame for our misplaced faith, of course. I hope he and the other polling aggregators learn humility from this experience. A Trump presidency will teach all of us many such lessons– if we survive it.

John from NC says:

This election would have been a Democratic Landslide if it were not for the first time in the history of all elections your media networks all selling out to ratings! From the first day of his announcing at Trump Plaza with paid actors as supporters (when has that ever happened) he has been covered with “free” air time. as a PR campaign pumping life into every ultra angry voter not able to focus on anything else, like facts! A circus, covered every night, to the detriment of ‘Fit candidates and journalistic integrity that used to provide facts for the most informed decision the voter can make!

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