538 Battlegrounds as of Mid-July

A month ago, we brought you the battleground states based on the site's model, and it's time for an update. Recall that the projection is not what would happen if the election were held today (that's the snapshot), but what 538 projects will be the November result.

Based on the data, we project 11 states inside of five points:



Five points is somewhat arbitrary (why not four, six, seven, etc.). One argument supporting five points is that ground organization and GOTV tends to not be able to make up much more margin against an accurate poll of voter preference. Whatever the dividing line, it is important to pick one number and stay consistent over updates. We've used five before; we'll stick with it.

Since the mid-June update, New Hampshire and North Dakota have moved outside the five-point range, toward Obama and McCain respectively. They remain the next two closest states outside the five-point dividing line (Pennsylvania ties New Hampshire at a 6.0% projected Obama win). Colorado has moved into the range, and all the other states have remained in place. Within the battleground group the states have jostled for ranking position, but given that Nate's tweaked the model a bit in the interim it's not worth attaching much importance to the tiny changes.

As for the Penumbra States, the model projects, eight McCain states will finish between 5-10 percentage points, for 81 EVs:



Seven Obama Penumbra States project between 5-10 percentage points, for 67 EVs:




Obama's safe base states (projected double-digit wins) total 175 EVs, while McCain's safe base states total 79 EVs. We project Minnesota as an 11.6% Obama win.

Adding in the 5-10 point projected wins, the totals are Obama 242, McCain 160. Last month, this projection was Obama 247, McCain 157.

Obama needs 28 EVs out of the battleground group for a clean win, 27 EVs for a tie and a messy but near-certain win. We predict Obama will win 51 EVs out of the 11-state battleground group.

The 538 mid-July projection: Obama 293, McCain 245.

Other 538 breakdowns:
Polling Average: Obama 309, McCain 229
Trend-Adjusted: Obama 309, McCain 229
538 Regression: Obama 298, McCain 240
Snapshot (if the election were held today): Obama 303, McCain 235

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Tipping Point v2.0

As I've hinted a couple of times, we now have a new version of the model running, which attempts to account for the interrelationships between polling movement in different states. Before I can work up the energy to fully describe that, let me first tell you about the new Tipping-Point States metric that I've developed to accompany it.

A Tipping-Point state is now defined as a states that would be most likely to alter the outcome of a close election if it were decided differently. More specifically, a Tipping-Point State is among the closest states –- taken alone or in combination –- that would give the losing candidate at least 270 electoral votes if transferred to him from the winner’s column, with no wasted electoral votes.

Let me give you a couple of examples. First, 2004, which is an easy one. The closest states won by Bush were New Mexico and Iowa. However, these would not have given John Kerry enough electoral votes even if he had won them. So the third-closest state, Ohio, was the lone Tipping-Point State for that election, since it would have gotten Kerry to 270 all on its own.

Now a somewhat more complicated example: 1960. Richard Nixon was 51 electoral votes shy of winning that election. The closest Kennedy states were as follows:

Hawaii (3)       -0.06%
Illinois (27)    -0.19%
Missouri (13)    -0.52%
New Mexico (4)   -0.74%
New Jersey (16)  -0.80%

So, we start with a 51-EV gap and begin whittling those numbers down for Nixon. Giving him Hawaii makes it 48, Illinois makes it 21, Missouri cuts Kennedy's lead to 8, and New Mexico to 4. And then we hit New Jersey, which gives Nixon the election. But it also gives him 12 extra electoral votes.

So we go back through the list in reverse order and see if there is any wastage. In this case, there is. If we place New Mexico back in the Kennedy column, Nixon still has 8 electoral votes to spare. In fact, while we must keep Missouri and Illinois, we can also eliminate Hawaii. So the Tipping-Point states for Nixon in 1960 were Illinois, Missouri, and New Jersey. This was the most efficient possible combination of states that would give him a winning electoral margin.

But I tried to slip one by you there. What do I mean by a "close election"? I mean one in which the electoral math matters. That was the purpose of the graph that I posted this morning:


The Tipping-Point calculation is weighted across each simulation based on the popular vote result predicted in each election. Specifically, it is weighted according to the probability that a candidate with that popular vote share will lose the Electoral College. So a simulation in which the popular vote is divided exactly evenly will be weighted at .5 -- the highest possible weighting. A simulation in which the popular vote margin is 3 points -- that gives the popular vote leader about a 97 percent chance of winning the election -- will be weighted at a .03. Basically, most of the calculation is derived from elections that are decided by a point or two.

So this definition is rather complicated mathematically -- but at the same time, I think it's more intuitive than the previous version. It's definitely a lot more robust.

The hot-off-the-presses Tipping Point numbers are as follows:



Michigan and Ohio will each prove to be decisive in a close election about 30 percent of the time. After that are Colorado and Virginia, which serve as gateways to their respective regions.

The really interesting thing is to compare the Tipping Point states with and without the intrastate (or should that be interstate?) correlations. A state like North Carolina is punished, for instance, for reasons that most of you can probably figure out. But we'll save that for later.

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Popular Vote v Electoral Vote, Part II

Here's another take on this: the probability, as determined by logistic regression of our latest simulation run, of the candidate winning the electoral vote based on his share of the popular vote.


So a 1-point popular vote win translates to about a 75 percent chance of winning the Electoral College, a 2-point win about a 90 percent chance, a 3-point win a 97 percent chance, and a 4-point win a 99 percent chance.

This is, of course, assuming that my simulation model is getting this approximately right. Note that I've lumped together McCain and Obama's numbers here, making the distribution exactly symmetrical. I don't know to what extent these numbers would hold with two different candidates and with a different set of states in play, but I'd bet it's pretty close to the mark.

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The Obama Eighteen

Courtesy of the Politico, Barack Obama’s campaign has telegraphed the electoral focus of its fall campaign. Three are its highest profile defenses (PA, WI, MI), one is a Kerry state in which McCain runs particularly well (NH), and 14 are Bush 2004 states where Obama thinks he has an opportunity to gain on the previous map (IA, NM, OH, CO, VA, FL, MO, NV, IN, ND, NC, MT, GA, AK).

Let's take a look at how FiveThirtyEight breaks down each of these states in terms of polling average, trend adjustment, 538 regression, and 538 prediction.



This map shows a baseline of Obama 200, McCain 139.

John McCain's best slicing and dicing of the public polling data within the 18 states is the polling average. Obama leads in Iowa (+6.2%), Wisconsin (+6.0%), New Hampshire (+6.0%), Pennsylvania (+5.5%), New Mexico (+4.3%), Ohio (+4.0%), Colorado (+2.5%), and Michigan (+1.9%) for a total of 93 EVs. McCain's states are North Dakota (+0.6%), Florida (+1.4%), Indiana (+1.8%), Missouri (+2.2%), Nevada (+2.8%), North Carolina (+4.7%), Alaska (+5.7%), Montana (+7.3%), and Georgia (+8.6%) for 93 EVs. Virginia is dead even, so after adding in the base EVs, the tally would be Obama 293, McCain 232, Unallocated 13.

When we adjust for trends in the polling data, we find ourselves in landslide territory. Obama leads in Iowa (+9.3%), New Hampshire (+9.0%), Wisconsin (+8.8%), Pennsylvania (+8.5%), Ohio (+7.1%), New Mexico (+6.1%), Colorado (+5.2%), Michigan (+4.6%), North Dakota (+4.4%), Virginia (+3.7%), Missouri (+3.3%), Indiana (+2.1%), and Florida (+1.0%), for a total of 158 EVs. McCain holds North Carolina (+0.5%), Nevada (+0.8%), Alaska (+2.8%), Montana (+3.1%), and Georgia (+5.4%), for 41 EVs. Under trend adjustment, the tally adding to our base would be Obama 358, McCain 180.

Under the 538 regression model, Obama leads in Iowa and New Hampshire (both +10.0%), Wisconsin (+8.7%), Pennsylvania (+8.6%), Michigan (+8.0%), Colorado (+7.1%), Ohio (+7.0%), Nevada (+5.4%), New Mexico (+5.2%), Virginia (+3.0%), Florida (+1.6%), and Missouri (+0.5%) for 149 EVs. McCain holds Montana (+0.3%), North Dakota (+2.0%), North Carolina (+2.5%), Alaska and Georgia (both +3.6%), and Indiana (+3.7%) for 50 EVs. Added to our base, the regression tally would be Obama 349, McCain 189.

Finally, the 538 projections as of June 25 show Obama winning Iowa (+9.4%), New Hampshire (+9.3%), Wisconsin (+8.8%), Pennsylvania (+8.5%), Ohio (+7.1%), New Mexico (+6.1%), Colorado (+5.8%), Michigan (+5.2%), Virginia (+3.6%), Missouri (+2.7%), Florida and Indiana (+1.1%) and Nevada (+0.7%) for 160 EVs. McCain projects to hold North Carolina (+0.8%), North Dakota (+0.9%), Montana (+1.8%), Alaska (+3.0%), and Georgia (+5.0%) for 39 EVs. With the baseline, Obama 360, McCain 178.

Under these numbers, McCain needs to gain 2.5% on the polling averages to win (adding Virginia, Michigan and Colorado). He needs to gain 5.2% on the trend analysis to win (to flip Florida, Indiana, Missouri, Virginia, North Dakota, Michigan and Colorado). Percentage-wise, McCain's toughest task is the regression model, since to win he has to gain 7.0% all the way up Obama's list to claim Ohio (Michigan, Florida, Virginia, New Mexico, Nevada and Ohio). Under our projection figures, McCain needs to reclaim Nevada, Indiana, Florida, Missouri, Virginia, Michigan and Colorado to win the presidency. That's a polling gain of up to 5.8%, again with Colorado being the final clinching state (working back up Obama's list) for the third of our four models.

The bad news for McCain in these numbers that among the "safe" Obama base states, Obama holds double-digit projection leads in every one of those states, with the lone exception of Oregon (+9.4%), discussed yesterday. Minnesota is next closest, projected at Obama +10.9%. The rest are just not remotely in play without a huge game-changing event in the race. Moreover, 538 currently projects a number of McCain's "safe" base states in single digits (alphabetically Arizona, Kansas, Louisiana, Mississippi, Nebraska, South Carolina, South Dakota, Tennessee, Texas, and West Virginia - see sidebar). While Obama isn't likely to win these states, our models show Obama coming closer to winning them as we sit here in late June than McCain is to winning safe Obama states like Delaware, Maine, Washington, etc.

Finally, there is the matter of the one EV in Nebraska's 2d congressional district, which Obama's camp explicitly added to the list of eighteen. Eventually, we will add broken-out data for this district and refer to the Obama-defined battlegrounds as "the 18.2."

If John McCain's camp identifies a similar roster of states it sees as battlegrounds, we will analyze that list as well.

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538's Battlegrounds as of Mid-June

Those with field experience may recognize the conventional wisdom/general rule that 5 points is the most a great field program's ground game can make up against an accurate poll of voter preference.

According to 538 regression analysis, there are currently eleven states closer than 5 points, most of which show McCain with a narrow lead to defend.

In order of closeness and color coded by who currently leads, they are:

1. Virginia, 0.2%
2. Missouri, 0.3%
3. Nevada, 0.6%
4. New Hampshire, 1.0%
5. Michigan, 1.5%
6. Ohio, 1.6%
7. Indiana, 1.7%
8. North Carolina, 3.3%
9. North Dakota, 3.8%
10. Florida, 4.0%
11. Montana, 4.5%

Electorally, the 39 states and DC that lie outside this 5-point range: Obama 252, McCain 157.

For what it's worth, there are twelve states between 5 and 10 points, and each candidate has 6 of them. Obama's are Colorado (+5.1%), Pennsylvania (+5.7%), New Mexico (+6.3%), Wisconsin (+6.4%), Iowa (+8.7%), and New Jersey (+9.4%), for a total of 67 EVs. McCain's are Alaska (+6.1%), South Dakota (+6.6%), West Virginia (+8.2%), Louisiana (+8.9%), South Carolina (+8.9%) and Georgia (+9.9%), for a total of 43 EVs.

What the 5-10% group tells us is that while Obama is currently pressing McCain hard in the under 5% group, if McCain could apply an across the board 2% adjustment in his favor in every state, suddenly there would be 11 states under 5% and McCain would hold a lead in seven states ranging in closeness from Ohio (+0.4%) to Indiana (+3.7%). Obama would hold a lead in four states ranging from Colorado (+3.1%) to Wisconsin (+4.4%) with Pennsylvania and New Mexico in between. And Obama would lead 207-205 electorally in the states outside the 5% margin.

If we want to arbitrarily mark the line at 8%, Obama leads 207-151 electorally with 17 states being inside that margin. Obama leads in 7 of those states that hold 86 EVs, and McCain leads in 10 with 94 EVs.

Obviously, the state races will change over time with some tightening and some being put away. Organization, energy and GOTV programs will make an impact, but we can only speculate right now as to which campaign will take better advantage of the ground game.

What's especially interesting about the close states is what a cultural range those states represent. Montana, New Hampshire, Virginia, Michigan, Nevada and Florida are all culturally such different states that it seems obvious the battle lines in this race haven't settled in yet. In a month or two after the country has had some time to size these two candidates up side by side, we should start seeing some stronger patterns emerge. But for now, let's be a little thankful that this isn't yet another dreary three-state race (OH, FL, PA).

UPDATE: With Nate's updates and new polling data tonight, some of the numbers have shifted. There are now twelve states under 5 points, as New Mexico became closer (+2.5%). Here's the new list, with the 38 + DC states outside the margin: Obama 247, McCain 157.

1. Missouri, 0.3%
2. Nevada, 0.4%
3. Indiana, 0.7%
4. Michigan, 1.6%
5. Virginia, 1.8%
6. Florida, 2.0%
7. New Mexico, 2.5%
8. New Hampshire, 2.6%
9. North Carolina, 2.7%
10. Ohio, 2.9%
11. North Dakota, 3.2%
12. Montana, 4.2%

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Popular Vote v Electoral Vote

This might be my favorite graph that we've done so far: a comparison of Barack Obama's popular and electoral vote totals across the first 1,000 simulations that we ran last night:



Several interesting things to point out:

1. The relationship between the popular vote and the electoral vote is approximately linear, except at the endpoints. As a rule of thumb, a gain of one percentage point in a Obama's popular vote share results in a gain of 25 electoral votes. This is also, you will note, a pretty steep slope. If Obama wins the election by 4 percentage points, he projects to win by approximately 100 electoral votes (319-219).

2. The regression line crosses the y-intercept at 269.3 electoral votes, which is almost exactly half of 538. That means that there does not appear to be any systematic advantage in the electoral vote math to one candidate or another, at least based on our present rendering of these numbers.

3. Where you do see a little bit of skew are those scenarios where one candidate wins by about 5-15 percentage points. In those cases, the winning candidate tends to win by more electoral votes than is predicted by the regression line. This is because an especially high number of states are within reach for one or another candidate. In contrast to 2004, when 16 states and the District of Columbia were decided by 20 or more points, very few are polling that way this year.

4. The range of possible outcomes given any specific value of the popular vote is about 80-100 electoral votes wide. For example, an Obama win by 5 percentage points could easily be associated with any number from about 290 electoral votes up to as many as 390, depending on how the individual states shake out. Likewise, for any given value of the electoral vote, the range of the popular vote margin is about 6 or 7 percentage points wide. What this means, among other things, is that it's virtually impossible for a candidate to win the electoral college while losing the popular vote by more than about 3 or 3.5 percentage points.

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Homework Assignment

I was asked this question by a highly-respected political writer and couldn't come up with any convenient way to provide him with an answer. Nor does there appear to be any guidance on Google. So let me pose it to the collective:

How many unique ways are there to acquire at least 270 electoral votes without any excess?

For example, one combination would be to win California, Connecticut, the District of Columbia, Hawaii, Illinois, Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, Ohio, Oregon, Pennsylvania, Rhode Island, Vermont, Washington and Wisconsin. That would be equal to 272 electoral votes (not coincidentally, these are the John Kerry states plus Ohio).

Note that there are no excess electoral votes in this combination: if you remove one of the states with three electoral votes, the number falls to 269, which is below the 270-EV cut-off. So winning all of these states plus North Dakota would not qualify, since the candidate has superfluous electoral votes. On the other hand, replacing Vermont with North Dakota would make for a unique combination.

Nothing of monetary value to be provided to the winner, but I will give you a big thank you and shout-out on the front page, and your name will be immortalized in Google and possibly in a national column. I'm hoping that there's some genius out there who can solve this problem in 15 minutes.

p.s. To keep things at least somewhat simple, we probably should not worry about the split electoral votes in Maine and Nebraska.

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How the Electoral College Hurts the GOP

There's been some discussion recently about the possibility that Barack Obama wins the popular vote and loses the electoral college; see Mark Ambinder for a pretty good articulation thereof. However, our simulation model thinks that this is actually a bigger worry for John McCain. It assigns McCain about a 5 percent chance to win the popular vote and lose the election, to Obama's 3 percent chance. So what gives?

There are a lot of different ways to approach this problem -- but there is one fundamental that should not be ignored. Namely, the allocation of electoral votes lags behind changes in the distribution of the population. Presently, the composition of the electoral college is based on the 2000 census -- what if it were based on the population in 2008 instead?

The Census Bureau does not yet have its current population estimate out for 2008. What we can do, however, is take its 2007 estimate, and then add to it the population gain between 2006 and 2007 to come up with a reasonable estimate for 2008. For example, Texas had 23.5 million people in 2006 and 23.9 million in 2007 -- a gain of about 400,000 persons. We add another 400,000 to account for population growth between 2007 and 2008, which gives us an estimate of 24.3 million for its current population.

If we do this for each state, and then reassign electoral votes based on the new population estimates, I show the following electoral votes changing hands:

- Texas gains three electoral votes.
- Arizona, Florida, Georgia, Nevada, South Carolina and Utah each gain one electoral vote.

- Iowa, Louisiana, Massachusetts, Michigan, New Jersey, New York and Pennsylvania each lose one electoral vote.
- Ohio loses two electoral votes.

As you can see, the gains tend to come in Republican-leaning states, and the losses in Democratic-leaning ones. We can be a little bit more specific about this by apportioning the electoral vote changes based on McCain and Obama's win percentages in each state. For example, we estimate that McCain has a 95 percent chance of winning Texas, so we assign McCain 95 percent of Texas' three new electoral votes (+2.85), giving Obama the small remainder of 0.15 electoral votes.



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