Pew: Growing Cell Phone Poll Bias Favors Republicans
First Posted: 10-13-10 05:41 PM | Updated: 10-14-10 05:14 AM
Does it matter that many polls -- including the vast majority that we are currently watching at the state and congressional district level -- do not call Americans who use only a cell phone and thus lack landline telephone service? Yes it does. It creates a growing bias that appears to benefit Republican candidates. That's the message of a new analysis released this afternoon by the Pew Research Center.
Since 2006, a rapidly increasing percentage of American households lacks landline phone service. The most recent government estimates find that one in four American households is reachable by cell phone only. Pollsters have been reluctant to sample and call Americans on their cell phones, partly because it costs more and partly because federal law requires hand dialing any call placed to a cell phone, which makes such calls less efficient and puts cell phone polling off limits to automated survey methodologies.
For the last four years, the Pew Research Center has conducted public opinion surveys involving separate, parallel samples of both landline and mobile phones. Their design allows for a comparison between combined samples of landline and cell interviews and samples based only on landline calls.
Before the 2008 election, they found that calling only landline phones introduced a "small but real" bias in favor of John McCain, an average bias of 2.3 percentage points on the margin on nine national surveys conducted between June and October of that year.
More:
http://www.huffingtonpost.com/2010/10/13/pew-research-cell-phone-p_n_761760.html~~~~~ Want a Republican? Use a Landline. A Democrat? Call a Cell Phone.
6 months ago
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... the Pew Research Center's final study for this year of the disparities between those interviewed by landline and those interviewed by cell phone further bolster its earlier findings that landline-only samples of voters skew the results toward Republicans.
Analyzing three of its own polls during 2010, Republicans held a lead that was an average 5.1 points higher in the landline-only samples than in the surveys that combined landlines and cell phones.
Pew said that in its final pre-election poll, the landline-only sample of likely voters put the Republicans ahead on the generic congressional ballot by 51 percent to 39 percent, but that lead fell to 48 percent to 42 percent when cell phone users were included in the sample. While the official figures are not yet final, the Republican margin in the national House vote ended up being about 7 points.
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Pew found that young people reached by cell phone differ politically from young people reached by landline.
Democrats had a 53 percent to 38 percent lead over Republicans among registered voters under 30 in Pew surveys this year that included both landline and cell phone users. But when it came to just those reached by landline, the Democratic edge fell from 49 percent to 45 percent.
One final note from Pew's findings: "Voter registration is lowest among those with only a cell phone -- just 60 percent are registered voters."
http://www.politicsdaily.com/2010/11/22/want-a-republican-use-a-landline-a-democrat-call-a-cell-phone/~~~~~Polling FAQ
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Do pollsters call cell phones?
No. It is illegal for them to do so. This fact means that people who have only a cell phone and no land line will be systematically excluded from polls. Since these people tend to be mostly young people, the pollsters intentionally overweight the 18-30 year olds to compensate for this effect, but as more people drop their landlines, it is becoming a serious issue. Here is a report on the issue and below is a graph taken from the report.
http://www.electoral-vote.com/evp2008/Info/polling-faq.html~~~~~Posted on Monday, October 18, 2010
Beware of polls that exclude cell phone-only voters
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Who are these cell phone-only people? According to the National Center for Health Statistics:
•The young: 49 percent of those aged 25-29, and 38 percent of those aged 18-24.
•The less educated: 25 percent of those with high school educations or less, the most wireless group.
•Students: 29 percent of people who go to school.
•Hispanics: 30 percent, the most wireless of any race or ethnicity, with African-Americans at 25 percent and non-Hispanic whites at 21 percent.
•The poor: 36 percent.
•Renters, 43 percent.
~snip~
Calling cell phones for a poll is more challenging and expensive than calling land lines.
First, Miringoff said, Federal Election Commission regulations require that they be dialed manually. Second, a questioner has to ask whether the person is driving or using heavy equipment. A "yes" answer requires a follow-up call later. Third, a high percentage of people with cell phones are younger than 18 and unable to vote. Fourth, more people refuse to answer the calls because they must pay for the air time; often pollsters compensate them, further driving up costs.
http://www.mcclatchydc.com/2010/10/18/102226/beware-of-polls-that-exclude-cell.html