Two months ago, John McCain garnered 57% support in his own home state of Arizona and led Barack Obama by 20%. Now Scott Rasmussen is claiming in just two months, McCain’s lead has fallen to 9% and now doesn’t even get a majority of his own home state voters to support him. All this has, according to Rasmussen, happened in a mere two months.
PRESIDENT – ARIZONA (Rasmussen)
John McCain (R) 49%
Barack Obama (D) 40%
This poll was done June 26th among 500 likely voters.
Now taking this a step further, there has been a lot questions about the partisan breakdown Rasmussen is using in his polls. Unfortunately Rasmussen refuses to release raw numbers, so we have to make some assumptions. Fortunately the Arizona Secretary of State publishes voter registration figures on a regular basis. As of June 1st, according to the AZ Secretary of State, the party registration in Arizona is as follows:
ARIZONA PARTY REGISTRATION
| Republicans |
1,045,365 |
38.2% |
| Democrats |
935,638 |
34.2% |
| Other/3rd Party |
753,105 |
27.5% |
The article indicates the following.
The Arizona Senator is supported by 81% of Republicans and enjoys a twelve point lead among unaffiliated voters. Obama gets the vote from 75% of Democrats.
Using the above breakdown and assuming the 11% undecided vote is the same among all three “parties”, you should get a lead of 50%-39% for McCain instead of the 49%-40% lead Rasmussen is claiming, which I would considered pretty close.
POLL BREAKDOWN
| DEMO |
McCain |
Obama |
Undecided |
GOP (38.2%) |
81% |
8% |
11% |
| DEM (34.2%) |
14% |
75% |
11% |
| OTH (27.5%) |
50.5% |
38.5% |
11% |
| Total |
49.6% |
39.2% |
11% |
To get the total numbers for each candidate, you would multiple their share of the vote for each party by the percentage of the electorate that party represents. For McCain:
0.382 x 81 + 0.342 x 14 + .275 x 50.5 = 49.6%
So based on this, it does appear that Rasmussen is using the correct partisan breakdown to calculate his poll results, at least for this particular poll. If you assume Democrats are slightly more excited, it would explain why Rasmussen shows it slightly closer than the actual party breakdown.