Obama—Romney 2012

Obama Romney
98.9% probability of winning 1.1% probability of winning
Mean of 311 electoral votes Mean of 227 electoral votes

Electoral College Map

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Electoral College Map

Georgia Alaska Arizona Arkansas California Colorado Delaware Connecticut Florida Mississippi Alabama Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia D.C. Washington West Virginia Wisconsin Wyoming

Huh. Four years ago at this time, I was frantically entering the eleven new polls that had come out on election day. Today…not so much. We get only one rather inconsequential poll, although because it is Maine, and the Congressional districts are reported, we get three new polls for the price of one.

start end sample % % %
st poll date date size MOE O R diff
ME Maine PRC 01-Nov 03-Nov 905 3.3 53.3 42.2 O+11.1
ME1 Maine PRC 01-Nov 03-Nov 469 56.7 39.0 O+17.7
ME2 Maine PRC 01-Nov 03-Nov 436 49.7 45.7 O+4.0

As a consequence, this analysis differs little from yesterday’s analysis.

After 100,000 simulated elections, Obama wins 98,946 times and Romney wins 1,054 times (including the 180 ties). Obama received (on average) 311 (+2) to Romney’s 227 (-2) electoral votes. In an election held now, Obama would have a 98.9% (+0.1%) probability of winning and Romney would have a 1.1% (-0.1%) probability of winning.

My prediction: Obama wins. It’s almost certain.

Here’s our look back over the race from a series of elections simulated every seven days using polls from 06 Nov 2011 to 06 Nov 2012, and including polls from the preceding seven days (FAQ).

The interesting thing is the very ragged, multimodal distribution of electoral votes seen in the graph below. The single most likely outcome in this race is an Obama victory with 303 electoral votes. There is a 9.2% probability of that happening.

Then it jumps to 332 electoral votes, with a 6% probability. And then to 318 electoral votes with a 3.8% probability. And so on.

The raggedness of the electoral votes distribution reflects that there are a non-trivial number of important states with large uncertainty. Florida is Romney’s but with only a 63% probability. Iowa is Obama’s but with only an 84% probability. North Carolina is in Romney’s column, but with a 74% probability, and Virginia goes to Obama, but with a 78% probability.

Ten most probable electoral vote outcomes for Obama (full distribution here):

  • 303 electoral votes with a 9.19% probability
  • 332 electoral votes with a 5.94% probability
  • 318 electoral votes with a 3.80% probability
  • 304 electoral votes with a 3.78% probability
  • 290 electoral votes with a 3.49% probability
  • 319 electoral votes with a 3.30% probability
  • 297 electoral votes with a 2.97% probability
  • 314 electoral votes with a 2.30% probability
  • 312 electoral votes with a 2.23% probability
  • 333 electoral votes with a 2.11% probability

After 100,000 simulations:

  • Obama wins 98.9%, Romney wins 1.1%.
  • Average (SE) EC votes for Obama: 310.7 (19.3)
  • Average (SE) EC votes for Romney: 227.3 (19.3)
  • Median (95% CI) EC votes for Obama: 308 (276, 347)
  • Median (95% CI) EC votes for Romney: 230 (191, 262)

Each column of this table shows the electoral vote total aggregated by different criteria for the probability of winning a state (Safe=100%, Strong=90%+, Leans=60%+, Weak=50%+):

Threshold Safe + Strong + Leans + Weak
Safe Obama 159
Strong Obama 124 283
Leans Obama 20 20 303
Weak Obama 0 0 0 303
Weak Romney 0 0 0 235
Leans Romney 46 46 235
Strong Romney 129 189
Safe Romney 60

This table summarizes results by state. Click on the poll count to see the individual polls included for the state.

0 0 EC # Total % % Obama Romney
8 4 Votes polls Votes Obama Romney % wins % wins
AL 9 1* 404 39.6 60.4 0.2 99.8
AK 3 0* (0) (100)
AZ 11 1 1069 46.5 53.5 5.1 94.9
AR 6 1* 571 34.9 65.1 0.0 100.0
CA 55 3* 2986 57.3 42.7 100.0 0.0
CO 9 5 4007 52.1 47.9 97.3 2.7
CT 7 1 1183 56.7 43.3 99.9 0.1
DE 3 0 (100) (0)
DC 3 1* 1173 91.6 8.4 100.0 0.0
FL 29 8 7066 49.7 50.3 37.3 62.7
GA 16 1 1276 46.4 53.6 3.1 96.9
HI 4 1* 1157 64.2 35.8 100.0 0.0
ID 4 1* 563 30.0 70.0 0.0 100.0
IL 20 1 1174 58.2 41.8 100.0 0.0
IN 11 1 570 45.3 54.7 5.7 94.3
IA 6 7 5348 51.0 49.0 84.4 15.6
KS 6 2* 1143 39.4 60.6 0.0 100.0
KY 8 1* 557 42.4 57.6 0.6 99.4
LA 8 1* 2548 37.9 62.1 0.0 100.0
ME 2 3 3005 55.9 44.1 100.0 0.0
ME1 1 2 1250 59.8 40.2 100.0 0.0
ME2 1 3 1700 52.2 47.8 89.7 10.3
MD 10 2* 1538 61.6 38.4 100.0 0.0
MA 11 3 2556 58.2 41.8 100.0 0.0
MI 16 5 4920 51.7 48.3 95.8 4.2
MN 10 3 1953 54.4 45.6 99.8 0.2
MS 6 2* 1420 43.2 56.8 0.0 100.0
MO 10 3 2536 45.1 54.9 0.0 100.0
MT 3 2 1411 45.7 54.3 1.2 98.8
NE 2 1 1119 43.2 56.8 0.0 100.0
NE1 1 1* 389 45.5 54.5 11.1 88.9
NE2 1 1* 646 47.4 52.6 17.4 82.6
NE3 1 1* 284 35.9 64.1 0.0 100.0
NV 6 2 1298 52.5 47.5 90.6 9.4
NH 4 8 6212 51.2 48.8 91.9 8.1
NJ 14 5* 3773 55.6 44.4 100.0 0.0
NM 5 2* 1307 54.8 45.2 99.0 1.0
NY 29 3* 1770 63.8 36.2 100.0 0.0
NC 15 3 2709 49.2 50.8 26.3 73.7
ND 3 4* 2563 42.6 57.4 0.0 100.0
OH 18 9 8649 51.5 48.5 97.9 2.1
OK 7 1* 279 35.8 64.2 0.1 99.9
OR 7 1 903 53.0 47.0 90.6 9.4
PA 20 5 3892 51.6 48.4 91.9 8.1
RI 4 1* 523 62.1 37.9 100.0 0.0
SC 9 3* 4199 48.2 51.8 4.1 95.9
SD 3 1 595 43.7 56.3 1.4 98.6
TN 11 1* 566 36.6 63.4 0.0 100.0
TX 38 1* 752 41.5 58.5 0.1 99.9
UT 6 1 594 26.3 73.7 0.0 100.0
VT 3 1* 415 71.3 28.7 100.0 0.0
VA 13 6 5538 50.7 49.3 77.5 22.5
WA 12 1 923 53.5 46.5 93.5 6.5
WV 5 1* 361 42.1 57.9 1.7 98.3
WI 10 2 2409 52.5 47.5 95.7 4.3
WY 3 0 (0) (100)

* An older poll was used (i.e. no recent polls exist).

Details of the methods are given in the FAQ.