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Politics : View from the Center and Left -- Ignore unavailable to you. Want to Upgrade?


To: Sam who wrote (207164)11/5/2012 4:19:36 PM
From: Win Smith  Read Replies (1) | Respond to of 541731
 
Rasmussen has a history of favoring Rs till election time, when he phases out the bias and falls in line with other polls so he can claim great accuracy after the election.

Gallup, I don't exactly understand. They usually have a D falloff when they switch from registered voters to likely voters about a month before the election, but their "likely voter" model aka turnout model doesn't come from scaling for fixed R/D ratio the way that the wingers have been demanding for this election season, and that Rasmussen seems to do until he wants accurate results. Rather, it comes from a bunch of ( a little indirect but definitely non-partisan ) questions about how likely the individual are to vote. I think their model likely hasn't worked very well this year, but I don't think they're playing Rasmussen's game either.

Here's a couple articles from Gallup on their method:

gallup.com
pollingmatters.gallup.com

Here's their "likely voter" party id results:
gallup.com

Here's their general party id results, I assume "registered voters"

gallup.com

I'll have to check back when they publish final numbers on this stuff. I don't know why their likely voter model swung so much more R this year The winger claim is that this is more like 2004 than 2008, but in 2004 election time D and R registered voters were pretty equal, this year, not so much.



To: Sam who wrote (207164)11/5/2012 5:06:05 PM
From: Alastair McIntosh  Read Replies (4) | Respond to of 541731
 
Nate silver's view of the amount by which different polling firms lean Democratic or Republican.

Calculating ‘House Effects’ of Polling Firms By NATE SILVER

One of the ways that our forecast model seeks to make polling data more robust is by calculating and adjusting for “house effects,” which are systematic tendencies for polling firms to favor either the Democratic or Republican candidate.

Fairly often, what is perceived as a change in the polls is really just a reflection of these tendencies. A polling firm that tends to show favorable results for Barack Obama might survey a state one week, showing him three percentage points ahead. A different polling firm that usually has favorable results for Mitt Romney comes out with a survey in the same state the next week, showing him up by two points. Rather than indicating a change in voter preferences, these results may just reflect the different techniques and assumptions that the polling firms have applied.

The chart below reflects our model’s current estimate of the house effects for some of the more prolific polling firms. (A polling firm with a Democratic house effect tends to show better numbers for Mr. Obama than in comparable surveys, while one with a Republican house effect tends to have good numbers for Mr. Romney.)


As you can see, there is a fairly wide spread in the polls this year. For instance, the firm Public Policy Polling shows results that are about three percentage points more favorable to Mr. Obama than the consensus of surveys. (How is the consensus determined? More about that in a moment.) Conversely, Gallup’s polls have been leaning Republican this year, by about 2.5 percentage points. (See the Huffington Post’s Mark Blumenthal for a good explanation as to why.)

Rasmussen Reports, which has had Republican-leaning results in the past, does so again this year. However, the tendency is not very strong – a Republican lean of about 1.3 points.

If you are used to looking at Rasmussen Reports polls, your impression may be that their partisan lean is stronger than that. This is not wrong, actually. However, some of the difference results from the fact that Rasmussen is polling likely voters, while many other polling firms are polling registered voters.

Continues at: fivethirtyeight.blogs.nytimes.com