We’ve made some modifications to the default ‘Swing States’ view on the interactive map based on recent polling. As before, this remains a bit tricky as the polling is surprisingly different in a number of states depending on who the Democratic candidate is. Visit our polling maps, which you can get to off the home page to see the current polls for each prospective November contest.

We have moved Tennessee, Kentucky and North Carolina from Swing to Republican, for an additional 34 likely McCain electoral votes. We have moved Illinois from Swing to Democratic for an additional 21 likely Clinton/Obama electoral votes. We have moved Minnesota and Michigan back into the Swing category as they are polling within the margin of error regardless of whom the Democrats nominate.

These changes don’t affect the overall theme — the November race continues to look very competitive, with a fairly large number of states polling quite closely.

**As always, we caution that state-by-state polls at this early date are of limited predictive value**

A good number of new polls have been released this week by SurveyUSA and Rasmussen; visit the McCain vs. Obama and McCain vs. Clinton maps to review.   The overall trend has been toward McCain, with both potential match-ups very close.   With the prospective Democratic nominees out there skewering each other on a daily basis to gain an edge, it makes sense that this would translate into better polling for McCain in the short run.

The number of swing states remains quite large.  We define these as states where the poll margin is +/- 5 points, which is a bit larger than the margin of error on most polls.  At this early stage, the swing states for McCain vs. Clinton seem to be largely in the upper midwest, roughly the same as we’ve seen in the last couple elections.   The swing states are much more dispersed in the McCain vs. Obama match-up, and include usually safe ‘red’ states like both Carolinas, North Dakota, Nebraska and even Alaska.

Virginia is essentially tied in both races and might be an important one to watch as we head through the summer and fall.  The last time Virginia went to the Democrats was in 1964.

We’ve added a map that is based on current polling for a prospective McCain v. Obama race. We’re working on one for McCain v. Clinton and hope to have that live this week.

The electoral map will change for the 2012 election, based on the results of the 2010 census. Article I, Section II of the U.S. Constitution specifies that a census will take place every ten years to (among other things) apportion representation in Congress. Since each state has one Electoral Vote for each senator and representative, these numbers shift over time since not all parts of the country are growing at the same pace.

We’ve taken a look at some Census population projections for 2010 and plugged them into the current formula for apportionment. These population projections were made before Hurricane Katrina, so we’ve made a slight modification for that, but otherwise we’ve left them along.

The real 2010 numbers will undoubtedly differ, and Congress could change the rules for apportionment, but we thought we’d present this early look at what states would gain or lose Electoral Votes starting with 2012 based on those estimates:

• +3: Texas
• +2: Florida
• +1: Arizona, California, Georgia, Nevada, Utah
• -1: Illinois, Iowa, Louisiana, Massachusetts, Missouri, Pennsylvania
• -2: New York, Ohio

No real surprises here - population continues to shift away from northern, industrial states to the sunbelt. Their likely will be more and/or different changes than the above. For example,

The results in New Hampshire this past Tuesday (1/8) and Rudy Guiliani’s strategy of not aggressively campaigning in these early states have made it impossible to determine who the likely nominees for either party will be. As a result, head-to-head polling is all over the place, depending on who the candidates are.

Until the 2008 nominees are clearer (hopefully after Super Tuesday on February 5), our Probability of 270 feature will be based on 2004 actual results, not a hypothetical matchup.

Please read this post before using the information that follows.

For those who missed our 11/26 post…. Our “Probability of 270″ beta feature (below the interactive map) contains some early general election polls of Giuliani vs. Clinton, along with 2004 actual results where polling wasn’t available. Usually, these were states with wide margins in 2004, which likely will still be one-sided in 2008. We’re not predicting Hillary and Rudy will be the candidates, but this combination seems at least as likely as any other, and it is one with the most polling available.

The polls that have come out in December have generally moved in the direction of Clinton. This is consistent with the difficulties Giuliani has had maintaining his numbers on the Republican side. These numbers will likely go back and forth, only gaining some consistency when the actual candidates come into view. So, just be aware that “The Probability of 270″ is favoring the Democratic side as of now, based on current polling.

Current Poll Sources:

Polling sources for 11/26/07 update:

• SurveyUSA: AL, CA, IA, KS, KY, MA, MN, NH, NM, OK, OR, VA, WA, WI
• Brown Univ: RI
• Critical Insights: ME
• Quinnipiac: CT, FL, NJ, NY, OH, PA
• Rasmussen: AR, AZ, CO, GA, IL, MD, MI, MO, NC, TN, TX, UT

The following states are still using 2004 results: AK, DC, DE, HI, ID, IN, LA, MS, MT, NE, ND, NV, SC, SD, VT, WV, WY

The following upgrades launched today (12/28/07):

• Your custom maps will be saved when you leave the site if cookies are enabled on your machine
• New default starting view:   2008 Swing States.  More or less based on actual Rudy  vs. Hillary polls right now, so will need some fine tuning as the actual candidates come into focus and the polls become more meaningful
• Cleaned up the presentation of default views vs. the map created by user

More coming soon…

**Update on 1/13/08   We’ve temporarily reverted this feature to display based on 2004 actual results.   Given the results in IA and NH, there are clearly no front runners yet in either party, and the polling is all over the place depending on which two candidates are compared.    Once it is more clear who the nominees will be (hopefully by Super Tuesday on Feb. 5), we will return to using 2008 actual polls and tie those into the swing states map.**

Please read this post before using the information that follows.

We’ve populated our “Probability of 270″ beta feature (below the interactive map) with some early general election polls of Giuliani vs. Clinton. We’re not predicting these will be the candidates, but this combination seems at least as likely as any other, and it is one with the most polling available.

Note that we weren’t able to locate polls for every state, and some polls are a couple months old. We tried to grab the most recent one available. Many of those states where polling wasn’t available were states with wide margins in 2004, which likely will still be one-sided in 2008. For these, and a few closer ones, we will continue to use the 2004 actual results until actual polls become available.

Given the above, we’re still going to keep this in ‘beta mode’ for the time being.

Polling sources for 11/26/07 update:

• SurveyUSA: AL, CA, IA, KS, KY, MA, MN, MO, NH, NM, NY, OH, OK, OR, VA, WA, WI
• Brown Univ: RI
• Critical Insights: ME
• MTSU: TN
• Quinnipiac: CT, FL, NJ, PA
• Rasmussen: AZ, AR, GA, IL, MD, MI, NC, TX
• RBI: CO

The following states are still using 2004 results: AK, DC, DE, HI, ID, IN, LA, MS, MT, NE, ND, NV, SC, SD, UT, VT, WV, WY

**Update on 2/25/08: With the number of candidates that have a realistic chance of being a nominee of the two major parties down to 3, we’re seeing more head-to-head polls come out. We’ve created a map that displays those polls for McCain vs. Obama and these numbers power our “Probability of 270 feature” which is discussed below. As we mention on the aforementioned map — and want to strongly reiterate here — state polls at this early point, while interesting, are of limited predictive value, and likely will be quite volatile until at least the party conventions.**

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We’ve added an interesting new feature for 2008 that we call the “Probability of Reaching 270″. This feature brings together your interactive map with current polling numbers and is a powerful new tool that we believe is unique to 270toWin.

When 12 or fewer states remain undecided on your 2008 map, these probabilities will dynamically update as you modify the outcome of a state. The idea here is to give you a snapshot, specific to your customized map and based on current polling, of how likely it is that each candidate will win.

These are mathematical calculations and not our predictions for the election. 270toWin is non-partisan and does not exist to make predictions. The purpose of 270toWin is to give you, the user of the site, the tools you need to make your own predictions.

A little background: Although it is rarely presented this way, statistical theory makes it possible to take the results of a scientifically-conducted state poll and calculate the probability that each candidate will actually win that state’s popular vote, and thus collect its Electoral Votes. Do that for each of the 50 states + DC, and sum up the likelihood of every possible combination and you can generate a probability that the candidate will reach the required 270 Electoral Votes.

Example: Let’s say that a scientifically conducted poll for Missouri (11 Electoral Votes) comes back 48% for Candidate A and 44% for Candidate B, with 8% other, undecided or some other response. The question we are trying to answer is: “Given these results, what is the probability that Candidate A will actually get more votes than Candidate B in Missouri?” Assuming a sample size of 600 (see #3 in Important Notes, below), the answer is about 85%. That means there is an 85% chance Candidate A will win the state’s 12 Electoral Votes.

Now let’s say that Missouri is the only undecided (tan) state on your interactive map and neither candidate is yet at 270, but either would reach 270 if they won Missouri. If you look down in the “Probability of Reaching 270″ area below the map, you would see that the party for Candidate A would show an 85% chance of reaching 270…. as there is an 85% chance they win Missouri, and that is the only thing still to be determined.

It gets more complicated pretty quickly as more states remain undecided, as every possible combination of winning/losing must be evaluated. For example, with 12 states remaining, there are over 4,000 possible outcomes…with 20 states, there are over 1,000,000. However, the fundamental approach remains unchanged regardless of how many states are undecided.

Important Notes

1. Most polls provide a result, with a margin of error (e.g. +/- 4%). Essentially what we are doing here is reversing that presentation to say - “Given the margin of error and the polling percentages, how likely is it that the poll’s predicted winner is correct?” Note that all we are interested in is the probability of winning here…a victory by 10 votes is the same as a victory by one million votes… the winner gets the Electoral College bounty for that state.
2. The calculated probabilities are valid even for results that are within the margin of error. As long as the poll is conducted properly, we can calculate how likely it is that the poll’s predicted winner is correct. Obviously, as the results narrow, the probabilities get closer to 50/50.
3. The sample size is important to the calculations as it impacts the margin of error. Larger sample size means a smaller margin of error. A smaller margin of error impacts the probability that the poll’s predicted winner is correct. For example, a Candidate A 48%- Candidate B 44% poll with sample size of 600 yields an 85% probability that A > B, while the same 48-44 result with a sample size of 1,200 yields a 93% probability that A > B. Sample size is often shown as “n =” when poll results are displayed.
4. Ties (269-269) can occur and the probability of a tie will be displayed in your results.

We’ve added a Margin of Victory overlay to the 2004 election historical map.   Just select ‘2004′ above the map on the home page, and then “Margin of Victory View” from the drop down below the map.