Pollster.com

August 3, 2007

POLL: Newsweek National Survey

By Eric Dienstfrey

A new Newsweek national survey of 1,002 adults (conducted 8/1) finds:

• 29% approve of the job George Bush is doing as president, 63% disapprove.

• Among 324 registered Republicans and those who lean Republican, former Mayor Rudy Giuliani leads former Sen. Fred Thompson (30% to 22%) in a national primary; Sen. John McCain and former Gov. Mitt Romney trails at 13%. All other candidates receive less than 5% each.

• Among 422 registered Democrats and those who lean Democratic, Sen. Hillary Clinton leads Sen. Barack Obama (44% to 23%) in a national primary; former Sen. John Edwards trails at 14%. All other candidates receive less than 5% each.

By Eric Dienstfrey on August 3, 2007 10:04 PM | Permalink | Comments (0) | TrackBacks (0)

Bush Approval: DemoCorps 36-Pew 29-Trend 30.8

By Charles Franklin

A new Greenberg Quinlan Rosner/Democracy Corps poll, taken 7/25-29/07 finds approval of President Bush at 36%, with disapproval at 60%. The new Pew Center poll, also taken 7/25-29/07 puts approval at 29%, disapproval at 61%.

With these two new polls the trend estimate of approval now stands at 30.8%.

The GQR/Democracy Corps poll is a statistical outlier, falling above the 95% confidence interval around the approval trend. At the moment we have two outliers-- ARG's 25% is below the confidence interval.

GQR/Democracy Corps polls are of likely voters, rather than adults as with most polls here. As a result, they consistently estimate approval levels higher than for the adult population and hence above the trend line as well. This is clear from the plot below showing "Greenberg" surveys tracking high. This is a "design decision" to survey likely voters, and should not be considered a defect in the poll. Inferences are to a different population from that of the general population.

The "house effect" estimate for GQR/Democracy Corps surveys is just below 3 percentage points, with a confidence interval from just under 2 to just under 4 points. Despite this substantial house effect, GQR surveys have only rarely exceeded the confidence interval for presidential approval.

As the number of recent polls has increased, the standard "blue line" estimator of support has increased it's "bend" and is coming closer to the more sensitive "red line" estimator, further evidence that approval trends changed direction around June 28, when the red estimator put approval at 28.7%. Currently the blue estimator agrees with that date as the turning point, though the estimate will continue to change until enough data are available for a stable estimate of the turning point.

While the change in support is now pretty clear, the reasons are less so. The timing coincides with a series of Supreme Court decisions, all carried by the majority created with Bush's appointments of Roberts and Alito. I don't think the Court is salient enough with the general population to be a strong driver of public opinion, especially of presidential approval. However, it is possible that the most politically involved conservatives were both aware of the decisions and gave Bush credit for his appointments, helping arrest his decline in the polls.

The other event about this time was the commutation of Scooter Libby's prison sentence on July 2. Initial reaction among the general population and even many self-described conservatives was disapproving of this decision. But here too the effect may have been positive among conservative Republicans and served to shore up support among that constituency.

But that said, unlike previous sharp turning points that have corresponded to major presidential speeches, this one is harder to account for with "obvious" actions of the President (or of Congress, for that matter.) I invite your speculation on this.

Cross-posted at Political Arithmetik.

By Charles Franklin on August 3, 2007 7:49 PM | Permalink | Comments (2) | TrackBacks (0)

POLL: ARG California, Alabama Primary

By Eric Dienstfrey

Two new statewide surveys from American Research Group of likely voters in California and Alabama (conducted 7/30 through 8/2) finds:

• Among 600 Democrats in California, Sen. Hillary Clinton leads Sen. Barack Obama (35% to 22%); former Sen. John Edwards trails at 16%, Sen. Joe Biden and Gov. Bill Richardson both at 5%. Among 600 Democrats in Alabama, Clinton (at 38%) leads both Edwards (19%) and Obama (17%). All other candidates receive less than 5% each.

• Among 600 Republicans in California, former Mayor Rudy Giuliani (at 30%) leads former Sen. Fred Thompson and former Gov. Mitt Romney (both at 18%); Sen. John McCain and former Speaker Newt Gingrich both trail at 7%. Among 600 Republicans in Alabama, Thompson leads Giuliani (31% to 26%); McCain trails at 16%, Gingrich at 8%. All other candidates receive less than 5% each.

View all California Primary poll data at Pollster.com here:

Democrats	Republicans

By Eric Dienstfrey on August 3, 2007 5:21 PM | Permalink | Comments (0) | TrackBacks (0)

POLL: ABC/Post Iowa Dem Caucus

By Eric Dienstfrey

A new ABC News/Washington Post statewide survey (ABC story, results; Post story, results) of 500 likely** Democratic caucus goers in Iowa (conducted 7/26 through 7/31) finds a "three-way tie" between Sen. Barack Obama (27%), Sen. Hillary Clinton (26%) and former Sen. John Edwards (26%); Gov Bill Richardson trails at 11%. All other candidates receive less than 5% each.

** Likely voters were chosen if the respondents said they were registered to vote in Iowa at their present address, if they were certain to attend or probably will attend the Iowa caucus, and if they would vote specifically in the Democratic Party caucus.

Democrats

By Eric Dienstfrey on August 3, 2007 4:12 PM | Permalink | Comments (6) | TrackBacks (0)

How Tight is the Screen? Part II

By Mark Blumenthal

I want to pick up where I left off on Tuesday, when I wrote about the way national surveys screen for primary voters. How well have the pollsters in early primary states done in disclosing how tightly they "screen" to identify the voters that will actually turn out to vote (or caucus)? Not very well, unfortunately.

For those just dropping in, here is the basic dilemma: Voter turnout in primary elections and, especially in caucus states like Iowa, is typically much lower than in the general election. A pre-election survey that aims to track and ultimately project the outcome of the "horse-race" -- the measure of voter preferences "if the election were held today" -- needs to represent the population of "likely voters." When the expected turnout is very low, that becomes a difficult task, especially when polling many months before an election.

And in Iowa and South Carolina, if history is a guide, that turnout will be a very small fraction of eligible adults,** as the following table shows:

When a pollster uses a random digit telephone methodology, they begin by randomly sampling adults in all households with landline telephone service. They need to use some mechanism to identify a probable electorate from within a sample of all adults. If recent history is a guide, the probable electorate in Iowa -- Democrats and Republicans -- will fall in the high single digits as a percentage of eligible adults. South Carolina's turnout is better, but is still unlikely to exceed 30% of adults. And while the New Hampshire primary typically draws the highest turnout of any of the presidential primaries, it still attracts less than half of the eligible adults in the state. Despite all the attention the New Hampshire primary receives, many voters that ultimately cast ballots in the November general election (roughly 30% in 2000) choose to skip their states' storied primary.

A pollster may not want to "screen" so that the size of their likely voter matches the exact level of turnout. Most campaign pollsters I have worked with prefer to shoot for a slightly more expansive universe, both to capture those genuinely uncertain about whether they will vote and to account for the presumption that "refusals" (those who hang up on their own before answering any questions) are more likely to be non-voters.

Nonetheless, the degree to which pollsters screen matters a great deal. If, hypothetically, one Democratic primary poll captures 10% of eligible adults while another captures 40%, the results could easily be very different (and I'll definitely put more faith in the first).

It also matters greatly how the pollster go about identifying likely voters. I wrote quite a bit about that process in October 2004 as it applies to random digit dial (RDD) surveys of general election voters. In extremely low turnout contests, such as the Iowa caucuses, most campaign pollsters now rely on samples drawn from lists of registered voters that include the vote history of individual voters. Most of the Democratic pollsters I know agree with Mark Mellman, who asserted in a must-read column in The Hill earlier this year that, "the only accurate way to poll the Iowa caucuses starts with the party's voter file."

So, based on the information they routinely release, what do we know about way the recent polls in Iowa, New Hampshire and South Carolina screened for likely voters? As the many questions marks in the tables below show, not much.

The gold star for disclosure goes to the automated pollster SurveyUSA. Of 22 survey organizations active so far in these states, they are the only organization that routinely releases (and makes available on their web site) all of the information necessary to determine how tightly they screen. Every release includes a simple statement like the one from their May poll of New Hampshire voters:

Filtering: 2,000 state of New Hampshire adults were interviewed by SurveyUSA 05/04/07 through 05/06/07. . . Of the 2,000 NH adults, 1,756 were registered to vote. Of them, 551 were identified by SurveyUSA as likely to vote in the Republican NH Primary, 589 were identified by SurveyUSA as likely to vote in the Democratic NH Primary, and were included in this survey.

I did the simple math using the number above (which are weighted values). For SurveyUSA's May survey, Democratic likely voters represented 29% of adults and Republican likely voters represented 28%, for a total of 57% of all New Hampshire adults. Their screen is a very reasonable fit for a survey fielded eight months before the primary.

Honorable mention for disclosure also goes to two Iowa polls. First, the Des Moines Register poll conducted by Selzer and Company. Ann Selzer provided me with very complete information upon request last year. Her first Iowa caucus survey last year used a registered voter list sample and screened reach a population that represents roughly 11% of the eligible adults (assuming 2.0 million registered voters in Iowa and 2.2 million eligible adults).

Second, the poll conducted in March by the University of Iowa. While their survey asked an open-ended vote question (rendering the results incomparable with those included in our Iowa chart), their release did at least provide the basic numbers concerning their likely voter screen. They interviewed 298 Democratic likely caucus goers and 178 Republican caucus-goers out of 1,290 "registered Iowa voters" (for an incidence of 37% of registered voters). Unfortunately, they did not specify whether they used a registered voter list or a random digit sample, although given the incidence of registered voters in Iowa, we can assume that the percentage of eligible adults that passed the screen was probably in the low 30s.

And speaking of the sampling frame, only 6 of 22 organizations SurveyUSA, Des Moines Register/Selzer, Fox News, Rasmussen Reports, Zogby, and Winthrop University specified the sampling method they used (random digit dial, RBS or listed telephone directory). I will give honorable mention to two more organizations -- Chernoff Newman/ MarketSearch and the partnership of Hamilton Beattie (D) and Ayres McHenry (R) -- that disclosed their sample method to me upon request earlier this year.

The obfuscation of this information by the remaining 14 pollsters is particularly stunning given that the ethical codes of both the American Association for Public Opinion Research (AAPOR) and the National Council on Public Polls (NCPP) include explicitly require the disclosure of the sampling method, also known as the sample "frame." The NCPP's principles of disclosure requires the following for its member organizations for "all reports of survey findings issued for public release:"

Sampling method employed (for example, random-digit dialed telephone sample, list-based telephone sample, area probability sample, probability mail sample, other probability sample, opt-in internet panel, non-probability convenience sample, use of any oversampling).

The AAPOR code mandates disclosure of:

A definition of the population under study, and a description of the sampling frame used to identify this population.

Finally, while virtually all of these surveys told us how many "likely primary voters" they selected, very few provided details on how they determined that voters (or caucus goers) were in fact "likely" to participate. The most notable exceptions were the Hamilton Beattie (D) Ayres McHenry (R) and Chernoff Newman/ MarketSearch polls in South Carolina, and the News 7/Suffolk University poll in New Hampshire. All of these included the questions used to screen for likely primary voters in the "filled-in" questionnaires that included full results.

So what should an educated poll consumer do? I have one more category of diagnostic questions to review, and then I want to propose something we might be able to do about the very limited methodological information available to us. For now, here's two-word hint of what I have in mind: "upon request."

Stay tuned.

**Political scientists typically use two statistics to calculate turnout among adults: all adults of voting age (also known as the voting age population or VAP), or all adults who are eligible to vote (or the voter eligible population or VEP). George Mason University Professor Michael McDonald has helped popularize VEP as a better way to calculate voter turnout, because it excludes adults ineligible for voting such as non-citizens and ineligible felons. The perfect statistic for comparison to telephone surveys of adults woul