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June 29, 2008 - July 5, 2008

 

July 3, 2008

Two Weeks Worth of "Outliers!"

By Mark Blumenthal

Desmoinesdem has some surprising advice for partisans on the receiving end of message testing polls they find offensive: don't hang up.

Kathy Frankovic ponders the potential for a perceived patriotism gap between McCain and Obama and reviews the problems that early voting creates for pollsters.

Frank Newport considers the value of pre-election polls in June, and lists five things you might not know about the election.

Gary Langer reviews misconceptions about the Hispanic vote.

Jennifer Agiesta reviews the Post/ABC numbers on McCain, Obama and Supreme Court appointments.

Kyle Dropp looks at public opinion on immigration.

Tom Schaller doubts Barack Obama can win in the South.

Nate Silver disagrees.

Election-Projection.net offers yet another election projection web site.

DemFromCt asks why the networks can't read polls.

Jay Cost considers Barack Obama's media buy strategy and his decision to forgo public funding.

David Hill doubts Barack Obama will convert GOP and independent youth and questions whether evangelical Christians will desert the Republicans.

Mark Mellman ponders what angers gun owners most, and addresses the "myth" that gay marriage initiatives determined the outcome of the 2004 election.

Jonathan Stein scores the Obama spreadsheet (via Bialik).

From last week, reviews on reaction to the Supreme Court's gun ownership decision from Jon Cohen, Gary Langer and Frank Newport,

And PPP polls the all-important topic of Andy Griffith and how his character might vote in 2008.

With that, we bid you a Happy 4th!

By Mark Blumenthal on July 3, 2008 6:14 PM | | Comments (9)

POLL: InsiderAdvantage Georgia

By Eric Dienstfrey

InsiderAdvantage/Majority Opinion
7/2/08 - 502 LV, 4.3%

Georgia (view our chart here)
McCain 46, Obama 44, Barr 4

By Eric Dienstfrey on July 3, 2008 5:15 PM | | Comments (16) | TrackBacks (0)

POLL: DailyKos Connecticut

By Eric Dienstfrey

Research 2000/
DailyKos.com (D)
6/30 through 7/2/08; 600 LV 4%

Connecticut (view our chart here)
Obama 57, McCain 35

By Eric Dienstfrey on July 3, 2008 4:05 PM | | Comments (7) | TrackBacks (0)

On Trackers

By Mark Blumenthal

My Nationaljournal.com column, on the differences between rolling-average tracking polls and other "traditional" surveys, is now online.

Regular readers may be interested in the chart in the column created by our own Charles Franklin (see below) and spiffed up considerably by the National Journal's Reuben Dalke (see the column). I wondered how the tracking poll trends compare to standard trend estimates that you see on our national chart. The chart that Franklin created plots the trends on the Obama margin (Obama percentage minus McCain percentage) using a loess regression trend line based on the non-overlapping releases from Gallup Daily, Rasmussen Reports and all other national polls. To make for a fair comparison, all three lines are plotted with the same sensitivity.

I was also curious how the trends would look if we simply "connected the dots" between the non-overlapping tracking poll releases by Gallup and Rasmussen tracking surveys as well as the "traditional" USA Today/Gallup results (based on "likely voters") . You see that below.

The Gallup Daily line looks more variable than what you are used to seeing on Gallup's Daily release, partly because the time scale is more compressed, partly because we are plotting the Obama-McCain margin rather than separate lines for each candidate and partly because we are plotting only every third or fifth day which eliminates the "smoothing" effect of the overlapping intermediate samples.

What conclusions do you draw?

Update: In the comments, PatrickM asks:

As to the sampling process for the Gallup tracking survey: I thought the purpose of the tracking survey was to draw a discrete sample each night. Since completion quotas are set for each night, non-respondents must necessarily be "replaced" for that night's calls. Theoretically, all these replacements should balance out if non-response is random.

But Gallup seems to be taking a second bite at this apple by drawing an entirely new sample on the second night and supplementing it with non-respondents from the first night until the nightly completion quota is reached. So theoretically, the 3-day rolling results could include data from the originally drawn sample point AND its doppelganger replacement phone number.

I'm not a sampling expert, but is there anybody out there who can describe the rationale behind why this is OK?

The best explanation I have seen of "rolling cross section design" (a more technically correct term than "rolling average") is Kate Kenski's description of the National Annenberg Election Survey (NAES) in Chapter 4 in Romer, Kenski, Winneg et. al., Capturing Campaign Dynamics 2000 & 2004 .

The NAES, ongoing now for 2008 but mostly held back for academic analysis, uses the same general "tracking design" as Gallup only with far more rigor: In 2004, they protocol involved dialing non-contacts as many as 18 times over as many as 14 days.

I won't try to summarize the whole chapter, but this paragraph gets closest to answering Patrick's question:

What is important to note here is that there were strict procedures in place so that no telephone number was treated differently from any of the other numbers selected. Telephone numbers released on Tuesdays were not handled differently from telephone numbers released on Fridays. This protocol ensures that the probability of being interviewed is a random event. By stabilizing the proportion of respondents who completed an interview after having been called numerous times, the representativeness of the daily cross-sections is maximized.

Why is it important that the date of the interview be a random event? if the date of interview is random, then the characteristics of the sample on any given day will not vary systematically.

By Mark Blumenthal on July 3, 2008 10:58 AM | | Comments (15)

POLL: Rasmussen Montana

By Eric Dienstfrey

Rasmussen Reports
7/3/08 - 500 LV, 4.5

Montana
Obama 48, McCain 43

By Eric Dienstfrey on July 3, 2008 10:27 AM | | Comments (21) | TrackBacks (0)

July 2, 2008

Comment of the Day

By Mark Blumenthal

From "joejoejoe," regarding yesterday's release of a new national survey from CNN/ORC:

Here's the headline to the CNN story that accompanies the poll.

'CNN poll: Obama, McCain in a statistical dead heat'

I'm not sure why a 5-point lead in a poll with a margin of error of +/- 3.5% is a "statistical dead heat" but whatever. Based on the '04 turnout a 1.5% victory projects to about 1.8 million more votes for Obama then for McCain. Doesn't "dead heat" mean tie?

Yes, it does, as as such "statistical dead heat" is a phrase we wish journalists would avoid.

To be fair, Nate Silver made the same point more emphatically (citing a National Council of Public Polls release) a few hours before joejoejoe. But we appreciate our alert readers nonetheless.

Update: A highly valued reader emails:

Not exactly. Suppose there are no undecideds and Obama leads 53-47. The +/- 3.5% MOE means that the estimate of 53% for the Obama has a 95% confidence interval ranging from 49.5% to 56.5%. 49.5% for Obama means 50.5% for McCain, so a McCain lead is within the margin of error. It's a little more complicated when there are undecideds, but the result would be similar

I probably posted this item too quickly. To me, and to most readers, "dead heat" means "tie." The point I agree with -- and the one made more directly by Nate Silver -- was not to imply that the 5 point margin was outside the margin of error, but rather to object to the use of the phrase "statistical tie" to describe a difference that is not quite large enough to attain statistical significance. It presumes we know the race is "a tie" when we lack the evidence, from this one poll, to be certain that a candidate is ahead.

Caution is always in order when it comes to interpreting small differences on just one poll result, but we have more than one poll to consider. Since May 1, we have logged 37 national poll releases (omitting daily tracking releases based on over-lapping samples). Only one (from Gallup) showed a "tie" result (44% to 44%). The other 36 had Obama ahead by margins of 1 to 15 percent. That's evidence that "tie" is not the best way to describe the current preferences in the race for president.

By Mark Blumenthal on July 2, 2008 4:32 PM | | Comments (9)

Poll: Daily Tracking for 7-02

By Mark Blumenthal

Gallup Daily
6/29-7/1/08; 2,665 RV

National
Obama 46, McCain 44

Also from Gallup:
As Independents Shrink, Democrats Gain
Hispanic Voters Solidly Behind Obama (video)

Rasmussen Reports

6/29-7/1/08; 3,000 LV

National
Obama 49, McCain 44

To see how these numbers compare with the current trend, view our National Presidential chart here.

By Mark Blumenthal on July 2, 2008 4:26 PM | | Comments (1)

POLL: Quinnipiac University Connecticut

By Mark Blumenthal

Quinnipiac University

Connecticut
n=2,437 likely voters, interviewed June 26-29

Obama 56%, McCain 35%

By Mark Blumenthal on July 2, 2008 11:17 AM | | Comments (11)

POLL: Strategic Vision Florida, Georgia

By Mark Blumenthal

The web site Political Wire published a sneak peak of at two new Strategic Vision (R) polls yesterday. While they included no information about survey dates and sample sizes, the reported the top-line numbers:

Florida: McCain 49%, Obama 41%, Barr 1%
Georgia: McCain 51%, Obama 43%, Barr 3%

We will update this entry (and our charts) with the results as soon we have the official release from Strategic Vision.

I corrected my typo and entered the numbers now posted by StrategicVision for Georgia and Florida. As of this writing the links for the releases appear to have the wrong release date (06/02/08) but list field dates of June 27-29 and a report different percentage for Obama in Florida (41%) than what PoliticalWire reported yesterday (43%).

By Mark Blumenthal on July 2, 2008 11:13 AM | | Comments (10)

July 1, 2008

POLL: CNN National

By Eric Dienstfrey

CNN/Opinion Research Corporation
6/26-29/08; 906 RV, 3.5%

National
Obama 50, McCain 45
Obama 46, McCain 43, Nader 6, Barr 3

To see how these numbers compare with the current trend, view our National Presidential chart here.

By Eric Dienstfrey on July 1, 2008 5:08 PM | | Comments (11) | TrackBacks (0)

POLL: Rasmussen Massachusetts

By Eric Dienstfrey

Rasmussen Reports
6/30/08 - 500 LV, 4.5%