17 October 2015

Clinton	Bush
35.2% probability of winning	64.8% probability of winning
Mean of 263 electoral votes	Mean of 275 electoral votes

There have only been something over a dozen new state head-to-head polls since the previous analysis of a general election match-up between Secretary Clinton and Gov. Bush. Previously, the race was, essentially, tied with Clinton having a slight edge. This month, the race is, well…tied. But now Bush has a slight advantage.

The trend can be seen from this graph created from a series of elections simulated every seven days using polls from 16 Oct 2014 to 16 Oct 2015, and including polls from the preceding month (FAQ).

In the month and a half since the previous analysis, the race has remained a tie, with a bounce in Bush’s favor followed by a bounce in Clinton’s favor. There isn’t much we can make of these bounces statistically. All of the data in the recent polls were collected before the Democratic debate, so we cannot even pretend the uptick in favor of Clinton is related to the debate. What is clear, however, is that this past summer, Clinton lost a significant edge she held over Bush.

For the most recent period, the 100,000 simulated elections, puts Clinton ahead 35,187 times and Bush ahead 64,813 times (including the 2,215 ties). Clinton received (on average) 263 to Bush’s 275 electoral votes. In an election held now, Clinton would have a 35.2% probability of winning and Bush would have a 64.8% probability of winning.

Here is the distribution of electoral votes [FAQ] from the simulations:

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

• 233 electoral votes with a 4.32% probability
• 244 electoral votes with a 3.85% probability
• 264 electoral votes with a 3.48% probability
• 249 electoral votes with a 3.43% probability
• 253 electoral votes with a 3.32% probability
• 260 electoral votes with a 3.22% probability
• 262 electoral votes with a 2.73% probability
• 282 electoral votes with a 2.58% probability
• 280 electoral votes with a 2.45% probability
• 257 electoral votes with a 2.24% probability

After 100,000 simulations:

• Clinton wins 35.2%, Bush wins 64.8%.
• Average (SE) EC votes for Clinton: 262.6 (20.9)
• Average (SE) EC votes for Bush: 275.4 (20.9)
• Median (95% CI) EC votes for Clinton: 262 (223, 307)
• Median (95% CI) EC votes for Bush: 276 (231, 315)

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 Clinton	142
Strong Clinton	81	223
Leans Clinton	10	10	233
Weak Clinton	11	11	11	244
Weak Bush	36	36	36	294
Leans Bush	31	31	258
Strong Bush	150	227
Safe Bush	77

An animated sequence of maps and electoral vote distributions can be seen here

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

	1	0	EC	#	Total	%	%	Clinton	Bush
	2	8	Votes	polls	Votes	Clinton	Bush	% wins	% wins
AL			9	0				(0)	(100)
AK			3	4*	2547	45.9	54.1	0.3	99.7
AZ			11	1*	492	50.0	50.0	50.8	49.2
AR			6	4*	3756	48.2	51.8	6.2	93.8
CA			55	2*	1546	57.2	42.8	100.0	0.0
CO			9	1*	948	46.7	53.3	8.5	91.5
CT			7	1*	1062	60.5	39.5	100.0	0.0
DE			3	0*				(100)	(0)
DC			3	0*				(100)	(0)
FL			29	3	2255	46.8	53.2	1.6	98.4
GA			16	1*	797	49.4	50.6	41.7	58.3
HI			4	0*				(100)	(0)
ID			4	1*	433	39.7	60.3	0.1	99.9
IL			20	1*	810	55.2	44.8	98.3	1.7
IN			11	0*				(0)	(100)
IA			6	2	2094	47.1	52.9	3.3	96.7
KS			6	5*	4536	44.8	55.2	0.0	100.0
KY			8	1*	975	45.4	54.6	2.1	97.9
LA			8	1	752	40.4	59.6	0.0	100.0
ME			2	1*	838	63.2	36.8	100.0	0.0
ME1			1	0*				(100)	(0)
ME2			1	0*				(100)	(0)
MD			10	1*	682	59.8	40.2	100.0	0.0
MA			11	1	378	65.1	34.9	100.0	0.0
MI			16	1	1172	53.2	46.8	93.6	6.4
MN			10	1*	873	51.2	48.8	69.4	30.6
MS			6	2*	1077	46.5	53.5	5.4	94.6
MO			10	1*	748	46.0	54.0	6.0	94.0
MT			3	1*	868	42.2	57.8	0.1	99.9
NE			2	0*				(0)	(100)
NE1			1	0*				(0)	(100)
NE2			1	0*				(0)	(100)
NE3			1	0*				(0)	(100)
NV			6	1*	582	57.0	43.0	99.0	1.0
NH			4	1	950	46.1	53.9	5.1	94.9
NJ			14	3*	2943	61.2	38.8	100.0	0.0
NM			5	2*	1232	58.5	41.5	100.0	0.0
NY			29	1*	727	59.6	40.4	100.0	0.0
NC			15	3	2571	47.6	52.4	4.5	95.5
ND			3	0				(0)	(100)
OH			18	1	991	48.8	51.2	31.1	68.9
OK			7	0				(0)	(100)
OR			7	1*	832	58.7	41.3	100.0	0.0
PA			20	2	1763	49.6	50.4	40.7	59.3
RI			4	0				(100)	(0)
SC			9	1*	937	44.1	55.9	0.6	99.4
SD			3	0*				(0)	(100)
TN			11	0*				(0)	(100)
TX			38	1*	393	43.5	56.5	3.7	96.3
UT			6	1*	538	25.8	74.2	0.0	100.0
VT			3	0*				(100)	(0)
VA			13	1	950	48.3	51.7	22.4	77.6
WA			12	2*	1593	55.6	44.4	99.9	0.1
WV			5	1*	999	42.2	57.8	0.0	100.0
WI			10	1	710	56.9	43.1	99.5	0.5
WY			3	1*	1071	34.8	65.2	0.0	100.0

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

Details of the methods are given in the FAQ.

The most recent analysis in this match-up can be found from this page.