There's a big disconnect between political watchers and the public when it comes to understanding the science of opinion polls. The public can see polls as definitive statements of fact, while political insiders know the results are only as good as the methodology.
Which is why a new gun control poll of six California congressional districts, paid for by a political nonprofit led by New York City Michael Bloomberg, raises so many questions.
Its headline proclaims broad support for new gun laws by the constituents of six California GOP congressmen; its conclusions, though, seem based on polling data that don't jibe with official voter registration stats.
"New Poll Finds 92 percent In California's 10th Congressional District Favor Mandatory Background Checks For All Gun Buyers," blasts the headline on Tuesday's press release from the group Mayors Against Illegal Guns. The poll was paid for by the group's 501 (c)(4) committee, the kind of organization used extensively in 2012 to funnel unlimited, anonymous donations into campaigns across the nation.
A representative of the organization later said the group paid for gun control opinion polls of 21 states and 41 individual congressional districts. All but four of the congressional districts polled are represented by Republicans.
And each of the California districts, with one notable exception, is represented by a Republican in a pretty competitive district. That exception: the Bakersfield district of Rep. Kevin McCarthy, the third-highest ranking GOP member of the U.S. House of Representatives.
The 10th congressional district, which is how the poll came to our attention, has about a 1-percentage point registration advantage for Democrats, with about 17 percent of its voters registered as independent (not with a political party). But the new poll, which suggests widespread support for new gun laws, apparently didn't sample voters in any way that's consistent with the real registration numbers.
(There's admittedly a difference between "identify as" and "registered," and a spokesperson confirmed that voters weren't asked about their actual registration.)
Data provided by the group shows 40 percent of respondents identify as Democrats and only 32 percent say they are Republicans. The poll also finds 24 percent of those surveyed identify as independents.
In other words, the poll seems to noticeably under-sample Republican viewpoints... in a district represented by a Republican... on an issue where there are stark differences between the two major parties as the 2013 debate gets underway.
The polling data for almost every other California congressional district shows a similar pattern: more Democrats or Democratic leaning voters than the voter registration rolls actually show.
That's not all. Comparing the demographic information provided about the poll with data provided by Political Data, Inc. (PDI), the gun control poll even further under-samples what PDI calls 'Republican-Plus' voters - that is, any voter who has previously voted a GOP ballot and/or donated to GOP campaigns. That group makes up 40.4 percent of voters in the district, compared to just 32 percent GOP respondents in the gun control group's poll.
A spokesperson for the political nonprofit behind the poll (and affiliated with the group of mayors) responded by calling the poll "a random sample." She also emailed back that she couldn't provide full questions and results at this point, but only a portion (called the "top line") of the poll.
With all of those caveats about the 10th congressional district voters who actually took the poll, the results suggest strong support for a federal law requiring background checks on all gun purchases, both from dealers and private owners (79 percent "strongly support"); and majority support on "reasonable restrictions" on gun ownership (58 percent "strongly support").
Keen eyes will focus on that last phrase - "reasonable restrictions," as the kind of subjective description not asked in public, independent polls. After all, an NRA card-carrying hunter may see "reasonable" as something far less restrictive than would a liberal, non-gun owner.
The poll clearly seems to have a political motivation, one that the news releases implies is supported by the group, Mayors Against Illegal Guns. 58 California mayors are listed as belonging to the organization, including Sacramento Mayor Kevin Johnson and the mayors of San Francisco, Los Angeles, and Oakland.
That political motivation is clear when you take a look at the districts: one represented by a Central Valley Republican who didn't draw a strong Democratic challenger in 2012, another in Southern California where Democrats could easily win but failed to get their candidate in the November runoff. And remember, too, that the man behind the national group - New York Mayor Michael Bloomberg - wrote a sizable check in support of freshman Rep. Gloria Negrete McLeod in her 35th congressional district win over former veteran Democratic congressman Joe Baca, precisely because he believed she was stronger on the issue of gun control.
The poll is interesting, but hardly scientific. It should probably be seen less as news, and more as a political warning to GOP incumbents when it comes to one of the most closely watched issues of 2013.