I had a conversation the other day about how cell phones might be making political polling less accurate. Cell phones are less likely to be called for political polls because they’re not generally listed in phone books, but there are a lot of people, especially younger people, who use cell phones exclusively and don’t bother with land lines at all. I speculated that because that demographic skews younger, it’s more likely that those folks support Obama than McCain.
Turns out I was right. Pew research just conducted a survey that compared the results from those with landlines and those with cell phones only (as well as those who had both, but used primarily their cell phone). The results are quite interesting. For example, when asked which candidate they were learning toward, the landline users split 46% for Obama and 41% for McCain; those who used cell phones exclusively were leaning 61% to Obama and 32% to McCain. That’s a huge difference.
The same result was there with Congress. When asked whether they were leaning toward voting for the Democrat or the Republican in their Congressional elections, landline only users split 52% to 37% for the Democrats; cell phone only users split 63% to 31%. Again, a huge difference. Here are the demographic numbers for both groups:
The number of Americans who have a cell phone but no landline phone has continued to grow, reaching a total of 14.5% of all adults during the last six months of 2007, according to U.S. government estimates. In addition, 22.3% of all adults live in households with both landline and cell phones but say that they receive all or almost all calls on their cell phones.
The cell-only and cell-mostly respondents in the Pew poll are different demographically from others. Compared with all respondents reached on a landline, both groups are significantly younger, more likely to be male, and less likely to be white. But the cell-only and cell-mostly also are different from one another on many characteristics. Compared with the cell-only, the cell-mostly group is more affluent, better educated, and more likely to be married, to have children, and to own a home.
It would be interesting to know how the major polling companies weight their results to account for those differences.