Free Republic
Browse · Search
General/Chat
Topics · Post Article

Skip to comments.

Polling: Sample Breakdown
February 2, 2005 | Michael Katz

Posted on 02/27/2006 7:40:07 PM PST by Mike10542

A question for freepers. What is the terminology polling organizations use to breakdown the polls between democrat, republicans, and independents. I know Rasmussen does it by the vote last election, 37%R, 37%D, 36%I. However, I notice in all these others polls the Dems usually consist of a larger sample. Now, I know we all talk about the fact that these outfits are doing it purposefully to make Bush look bad. However, I wonder if anyone knows what there response would be when asked why they oversample Democrats. Is there actually a technical reason why they do so besides bias? Are they coming to the breakdowns by another means besides how the voting broke down in the 2004 election? Thanks.


TOPICS:
KEYWORDS:

1 posted on 02/27/2006 7:40:08 PM PST by Mike10542
[ Post Reply | Private Reply | View Replies]

To: Mike10542
Is there actually a technical reason why they do so besides bias?

yes, beside being bias they are delusional.

2 posted on 02/27/2006 7:43:11 PM PST by Always Right
[ Post Reply | Private Reply | To 1 | View Replies]

To: Mike10542

Here's the long and short of it: CBS has Bush at 34%. Almost certainly an outlier. (Short lesson: when they say margin of error is + or - 3 points, for example, that only means that 95% of the time the results of the poll are within 3% of what they would be if you asked every single person. Suppose a group is evenly divided on an issue. What's to prevent you from getting a sample of 80 for and 20 against? Nothing. It just doesn't happen much. It is a rare outlier, but it will happen on occasion. Usually the outlier will only be a few points off the margin of error.) If you look at the Real Clear Politics composite of polls, Bush is running about 40%. The ports thing killed him. When I heard Chuckie Schumer say a couple of sentences on the ports that I agreed with, I could have thought I had died and gone to purgatory or something...


3 posted on 02/27/2006 7:44:56 PM PST by guitarist
[ Post Reply | Private Reply | To 1 | View Replies]

To: Mike10542

Because most democrats will whine to anyone who will listen, while Republicans tend to have enough sense to hang up when pollsters call.


4 posted on 02/27/2006 7:45:17 PM PST by jpf
[ Post Reply | Private Reply | To 1 | View Replies]

To: Mike10542

The argument for NOT weighting for party affiliation is as good or better than the argument FOR doing so. You just have to use big samples and look at multiple polls. But remember that as more people use cell phones and refuse to answer pollsters' questions, the polls are going to be unreliable oftener...


5 posted on 02/27/2006 7:46:31 PM PST by guitarist
[ Post Reply | Private Reply | To 1 | View Replies]

To: Mike10542

I certainly think CBS is biased--don't get me wrong--but I don't think they "cheat" on their polls to make Bush's numbers worse. I don't think they do. But I wouldn't be all that surprised if it turned out I were wrong!


6 posted on 02/27/2006 7:47:46 PM PST by guitarist
[ Post Reply | Private Reply | To 1 | View Replies]

To: Mike10542
It seems a great many of these polls over sample democrats. There was a NY Times poll (On the NYT webpage you can see the internals on their polls-in one recent poll 20% of respondents were black which would of course favor democrats) where dems were oversampled.

Of course there is a popular belief that polls done over the weekend favor dems because republicans are out shopping and traveling. I used to work for a market research firm and I always felt that people with unlisted phone numbers were more likely to be republicans than democrats.

Theres anoth theory that says the more successful you are the later you eat dinner when survey people are likely to call.

Survey firms are supposed to make an effort to balance the respondents but since so many of these polls are agenda-driven and soon as they get thierr 300 respondents they run with the results unless they have results they don't like (for example notice that we never say any polls on whether Karl Rove should be indicted or not).

7 posted on 02/27/2006 7:48:49 PM PST by buckeyesrule (Its only 30 more days till the baseball season starts!!!!!)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Mike10542

This latest poll sampled over 40% democrats, and less then 27% republicans. More BS from CBS.


8 posted on 02/27/2006 7:51:52 PM PST by STU_1963 (Life is better without liberals)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Mike10542
This is what Gallup said back in 2004 when they were accused of "oversampling" Republicans:

We've had many inquiries and comments about the latest Gallup Poll trial heat results on the presidential race. Our editorial team will be responding to as many of the issues raised as possible here over the next day or two.

One question that comes up frequently (and apparently is based on various statements bouncing around the Net) concerns the party identification of the respondents in our sample. The supposition on the part of some is that these party identification figures from poll to poll should be constant and the same as some standard established from previous polling.

That's simply not the correct way to look at party identification. At Gallup (as is the case for many other polling firms), we ask party identification at the end of the survey using this wording: " In politics, as of today, do you consider yourself a Republican, a Democrat, or an independent? " Our experience tells us that this is not a fixed demographic measure (like age or gender or ethnicity), but rather is a variable in and of itself. While many Americans are hard-core Republicans or hard-core Democrats and never would call themselves anything different, there is a group of Americans who have no firm party allegiance and whose political identification can and does shift during an election season.

In fact, if one candidate is doing particularly well, it is usually the case that more people in the sample will identify with that candidate's party. Thus, if Kerry is having a good period of time in the campaign (as was the case after the Democratic primaries last February and March, and again in June and July of this summer), then more people will identify as Democrats at the end of the questionnaire when we ask with which party they identify "as of today." If Bush is doing better, as he is now, then more people at the end of the questionnaire will identify as Republicans.

Furthermore, there are no Census or official figures on party identification nationally. A number of states do not require party registration, and what a person calls himself or herself can vary significantly from week to week or month to month.

So it is incorrect to say that a poll's showing one candidate to be ahead is the result of the fact that there are too many members of his party in the sample. In fact, that there are more people identifying with a leading candidate's party is a result of the same forces that are pushing that candidate into the lead.

One final note. Gallup (and other reputable pollsters) do carefully analyze the compositions of each sample on known demographic measures for which there are solid Census figures: age, gender, region of country, ethnicity, and education. And we do weight each sample to each of these if necessary, using complex and accepted statistical procedures. So our samples are remarkably constant from poll to poll on known demographic and regional measures. But in a political year we don't expect that samples will be the same from poll to poll in terms of party identification, any more than we expect the samples to be the same from poll to poll in terms of the choice of candidate for whom the respondents are voting.

9 posted on 02/27/2006 8:09:19 PM PST by RWR8189 (George Allen for President)
[ Post Reply | Private Reply | To 1 | View Replies]

To: RWR8189

I would call it a "prior" distribution, whereas the estimate is the "posterior" distribution. 37+37+36 = 110. Perhaps it's 26% independent?

Anyway, the posterior is sum over the prior. So if your prior is 37% Republican, 37% Democrat, and 26% Independent,
and the crosstabulation is:

R D I
R .90 .10 .50
D .10 .90 .40
I 0 0 .10

Columns indicate with which group the voter associates, and the rows indicate for which party the voter intends to vote.

Then the posterior is:

R = .90*.37 + .10*.37 + .50*.26 = 0.50
D = .10*.37 + .90*.37 + .40*.26 = 0.474
I = .10*.26 = 0.026

Now yes turnout does vary from one election to the next. So it may not make sense to set the prior equal to the result of the previous election. However it shouldn't be the arbitrary choice of the pollster either. Maybe one response should be "I intend to stay home for this election" and then the prior should be equal to the previous election.

Hmmm...you'd have to count voters leaving the system (deaths, expired registrations, moving) as well as those entering the system (coming of voting age, new registrations, moving) somehow.

Yeah, I know, in Philadelphia and Chicago, voters never leave the system.



10 posted on 02/27/2006 8:56:59 PM PST by scrabblehack
[ Post Reply | Private Reply | To 9 | View Replies]

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
General/Chat
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson