Over the past few years, statisticians and their fellow travelers have been
nervously tracking the growth of the cellphone-only population to determine whether omitting this group will significantly skew the results of the polls they produce. Now, data from the Pew Research Center for the People and the Press indicates that it is no longer a smart idea to fail to include cell-only users in telephone survey samples. A few days ago, Pew published a study looking at how the growing cell-only population is influencing polling for the presidential race. Pew concludes that while including cell phone users in the survey sample does not sway the aggregate results overly much, it reveals that cell-only users are much more likely to be young and support Senator Barack Obama. Pew reports that:
“In the pooled data, cell-only young people are considerably less likely than young people reached by landline to identify with or lean to the Republican Party, and even less likely to say they support John McCain. . . Among the cell-only respondents under age 30, there is a 34-point gap - 62% are Democrats, 28% Republican.”*
Pew concludes that: “Even though the omission of cell phones from election polls does not currently make a large difference in the substantive results, Pew's surveys this year suggest at least the possibility of a small bias in landline surveys.”
What does this mean for those conducting telephone-based market research? Well, when studying small shifts in behavior and attitudes where skews on either side can determine whether or not the results are statistically significant, it’s best to be doubly sure that you include cellphone-only users in your sample.
All of this is fascinating stuff. To learn more about US government surveys tracking the growth of the cell-phone only population, please click here.
*If you are of the mind that young people don’t (and won’t vote), see this nugget from Pew’s research: “While 18-29-year-olds reached by cell phone tend to have less experience voting than their landline counterparts, they are just as interested in the 2008 campaign, and express just as much intention to vote this year.”
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