A quick follow-up on my post last night about the conflicting results from Gallup on the Democratic presidential race as measured by two different national surveys: The latest USA Today/Gallup survey and the entirely separate Gallup Daily tracking. I exchanged email with Gallup's Frank Newport and can clarify two issues.
First, Newport promises further analysis on the difference between the two surveys, perhaps later this afternoon. We will link when available.
Second, the two Gallup surveys differed slightly in the the populations that were asked the primary vote preference question (which means that I assumed wrong in a comment I posted in the previous entry). The USA Today/Gallup poll reports Democratic presidential preference of all adult Democratic identifiers and "leaners" (those that initially identify as Democrats but say on a follow-up question that they "lean" Democratic). It does not screen for registration or vote intent.
As explained by Gallup's Jeff Jones in a post here three weeks ago, the Gallup Daily tracking screens further for adult partisans who also say they have voted or intend to participate in the Democratic primary or caucus in their state. They include:
Republicans or Republican-leaning independents who say they are extremely, very or somewhat likely to vote in their state's primary or caucus when it is held.
Democrats or Democratic-leaning independents who say they are extremely, very or somewhat likely to vote in their state's primary or caucus when it is held.
We [also] make provisions for those residing in states that have already held their primary caucus - those who indicate they have already voted are considered extremely likely to vote, and those who did not vote in their state's primary or caucus would be excluded from the base.
However, Newport adds that the different screen "would not by any means in and of itself account for the differences in the results between the two polls." Presumably, their upcoming analysis will elaborate.
Third, with the help of Gallup releases sent to my National Journal colleagues, I can report on the questions that preceded vote preference on the USA Today/Gallup survey:
First, we have some questions about the election for president, which will be held in November; that is, in November 2008.
1A. How much thought have you given to the upcoming election for president -- quite a lot, or only a little?
2. Do you approve or disapprove of the way George W. Bush is handling his job as president?
3. Next, we'd like to get your overall opinion of some people in the news. As I read each name, please say if you have a favorable or unfavorable opinion of these people -- or if you have never heard of them. How about --
[ITEMS A-C RANDOM ORDER, THEN ITEM D ASKED, THEN ITEMS E-G RANDOM ORDER]?
A. Hillary Clinton
B. John McCain
C. Barack Obama
[Note: E-G were omitted from the release]
4. (Asked of Republicans and independents who lean to the Republican Party) Next, I'm going to read a list of people who are running in the Republican primary for president. After I read all the names, please tell me which of those candidates you would be most likely to support for the Republican nomination for president in 2008, or if you would support someone else. [ROTATED: Former Arkansas Governor, Mike Huckabee; Arizona Senator, John McCain; Texas Congressman, Ron Paul; former ambassador, Alan Keyes]
5. (Asked of Republicans and independents who lean to the Republican Party) Which comes closer to your view about Mike Huckabee’s campaign for the Republican nomination for president-- [ROTATED: He should drop out of the race, (or) he should continue his campaign]?
6. (Asked of Democrats and independents who lean to the Democratic Party) Next, I'm going to read a list of people are running in the Democratic primary for president. After I read all the names, please tell me which of those candidates you would be most likely to support for the Democratic nomination for president in 2008, or if you would support someone else. [ROTATED: New York Senator, Hillary Clinton; Former Alaska Senator, Mike Gravel; Illinois Senator, Barack Obama].
ABC News polling director Gary Langer blogged on the conflicting national results, and he points out that "question order always is a possible culprit, but it doesn't usually make for differences like these." True, though it would be useful to know what questions precede the vote preference on the Gallup Daily tracker.
Langer also concludes with this bit of advice worth repeating about the four recent national polls (including one from CBS/New York Times showing Obama ahead by 16 points and one by AP/IPSOS showing Obama with a nominal 3 point lead):
For the moment, with the cause of these differing estimates up in the air, when considering the two national polls that show Obama ahead it would be prudent also to keep in mind the two that show the race essentially tied.