Five Thirty Eight Model: Trump Wins Georgia, But Clinton Wins Nationally in a Landslide

The FiveThirtyEight.com Polls-Plus model has Hillary Clinton winning the presidency. Credit: FiveThirtyEight.com
The FiveThirtyEight.com Polls-Plus model has
Hillary Clinton winning the presidency.
Credit: FiveThirtyEight.com
Nate Silver, who runs the popular polling / prediction site FiveThirtyEight.com, developed a forecasting model that correctly picked the outcome of the 2012 presidential election. Now, he is out with the 2016 version, which is based on the one used in 2012, but has been improved, notably by splitting the model into three separate forecasts, using slightly different variables.

The easiest to understand is the polls only model, which determines the odds of a candidate winning a given state based on how that candidate did in recent polling. That model also accounts for how much time is left until the election, and looks at polling in nearby or politically similar states for guidance. The second model is called now-cast, and it uses the same inputs as the polling only model, except it assumes that the election is held today, not four months from now. As a result, the now-cast model’s assumptions are more liberal than the polls only model. The final model, polls plus, uses economic data and past voter behavior to make assumptions about how the election will turn out.

Unlike other models, FiveThirtyEight doesn’t assign categories such as solid, likely or lean to a state. Instead, it determines the chances for each candidate to win each state. By simulating the election thousands of times using the state data, the model comes up with a national result.

What does all that mean? All three forecasts agree that in January, Chief Justice Roberts will swear in President Hillary Clinton, although there’s a good chance that Donald Trump will win in Georgia. Using the polls only model, there is an 80.3% chance that Clinton wins nationally, but a 56.8% chance the Trump wins in Georgia. Clinton would have 354 electoral college votes to Trump’s 183. The now-cast model increases the chances of a Clinton romp nationally, with an 85.5% chance of winning, compared to 14.5% for Trump. There’s not much change in the Peach State results, though. There’s a 56.4 chance Trump would win, compared to a 43.6% chance for Clinton. Hillary picks up another four electoral college votes in this model to 358.

Perhaps because it uses historical data, the polls plus model has Georgia solidly in red territory, with Trump having a 73.2 chance of winning here, compared to a 26.7% chance for Clinton. Nationally, however, the race tightens up, with a 73.5% chance of a Clinton victory, 26.5 chance for Trump. In this scenario, the electoral college elects Clinton, 319 votes to 219 votes.

One more thing of note: It appears that these models began tracking data in early June. Since then, the odds of a Clinton win have greatly increased. In the national polls-plus model the odds of a Clinton win have increased from 62.9% to 73.5% since June 8th. The Georgia polls-plus model has the chance of a Trump win here declining from 80.5% to 73.2%. The polls-only model is even worse, with Trump having a 70.3% chance of winning back on June 8th to a 56.8% chance today, a drop of 13.5 points.

The two parties have their conventions next month. It will be interesting to see what, if anything, has changed in the forecast at the end of July.

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The Eiger
The Eiger

I was about to post this on the morning reads, but this seems a more appropriate place.

It’s almost like Trump doesn’t want to win. Hillary is outspending him $140 million to $0 in ad time already purchased. Oh, and there is the fact that his people are just plain stupid and tried to solicit illegal campaign donations from members of Parliament. Ignorance can be fixed, but stupidity cannot.

“If you include all ad time reserved in battleground states through Election Day, the advantage is … $140 million to zero.”

http://hotair.com/archives/2016/06/29/battleground-ad-spending-in-june-team-hillary-26-million-team-trump-0/

Benevolus
Benevolus

“It’s almost like Trump doesn’t want to win”

I suspect he is just as surprised as everyone else that he has made it this far.

xdog
xdog

Not just Parliament, but Icelandic Parliament. You have to wonder who’s building those mail lists.

My off-the-wall prediction is Utah going for Clinton–it’s Romney’s home state, it’s filled with Mormons who despise Trump, and their L-G recently made a public affirmation of support for LGTB folks.

Oh, Silver correctly forecast 49 out of 50 states in 2008 and every state in 2012.

The Eiger
The Eiger

It’s sad, but you could be right. My prediction is that John McCain loses this November as well becasue Trump will be that big of a drag on the ticket in Arizona. If the democrats were running a real candidate against Johnny, then Georgia may be in play.

edatlanta
edatlanta

At the risk of sounding like I’m throwing shade… 43 states *anyone* can accurately predict. Of the remaining seven, two have a good shot of going blue so you’ve got a 50/50 shot of getting the other five. Not necessarily a big accomplishment, IMO

Andrew C. Pope
Andrew C. Pope

Especially considering ’08 and ’12 involved Barack Obama running against a bowl of potato salad that was left out in the sun for 3 hours.

xdog
xdog

I get what you’re saying but if it was that easy, more people would have matched Silver’s accuracy, including Gallup and whoever Romney was paying.

Here’s the 538 staff chat on what the model means: http://fivethirtyeight.com/features/an-80-percent-shot-doesnt-mean-clinton-is-a-sure-thing/

billdawers
billdawers

It’s worth remembering that a huge number of pundits predicted that the 2012 election was going to be much closer than it was and many predicted a Romney win. Romney’s own camp thought they were going to win as they went into election day. The weeks before the election were filled with commentary about biased polling, and a number of prominent media figures outright attacked Silver or dismissed his work (which they never really understood).

Andrew C. Pope
Andrew C. Pope

True, I feel there are two factors at play. 1) Silver is/was a statistician who cares more about getting the numbers “right” than he does about anything else. The news media depends on the “horse race” nature of an election to drive ratings. If CNN were to go on air and say “welp, Obama has this thing shored up, let’s just sit around and twiddle our thumbs until a pretty white toddler goes missing on board a Malaysian airlines jet,” no on would stick around. 2) The folks thinking the polls were skewed tended to come from the right We… Read more »