The politics of cell phones

By E.J. Dionne

The Pew Research Center has performed an important piece of analysis that ought to shape the way we look at polls over the next two years. And its findings have real political impact, so please read on even if you're not obsessed with public opinion surveys.

There has been much debate in recent years over whether telephone surveys conducted only on landlines have produced distorted findings because so many Americans, particularly the young, now use only cell phones only. Pew has shown that this fear is justified. And it notes that this problem is growing. In essence, landline-only polls give the Republicans a measurable advantage.

Here's the key finding: "Across three Pew Research polls conducted in fall 2010 -- conducted among 5,216 likely voters, including 1,712 interviewed on cell phones -- the GOP held a lead that was on average 5.1 percentage points larger in the landline sample than in the combined landline and cell phone sample."

There's a reason for this. As Pew's report notes: "The difference in estimates produced by landline and dual frame samples is a consequence not only of the inclusion of the cell phone-only voters who are missed by landline surveys, but also of those with both landline and cell phones -- so called dual users -- who are reached by cell phone. Dual users reached on their cell phone differ demographically and attitudinally from those reached on their landline phone. They are younger, more likely to be black or Hispanic, less likely to be college graduates, less conservative and more Democratic in their vote preference than dual users reached by landline. " (My emphasis added.)

Pew also found that the difference between samples that included cell phone users and those that did not had grown substantially since 2008, when "Barack Obama's lead over John McCain was on average 2.4 percentage points smaller in the landline samples than in the combined samples."

Okay, but the next election is almost two years away, so why does this matter now?

Between now and then, pollsters will conduct hundreds of surveys and their results will be averaged in together by many Web sites. These surveys will measure the popularity of President Obama, of Republicans and Democrats in Congress - and also public attitudes on many issues. We now know that surveys that poll only landline users will be skewed significantly in a conservative direction. And like it or not, surveys influence public opinion and (I know this is hard to believe) even the votes of some members of Congress on key issues. The public, for example, is split on the repeal of health-care reform. Landline-only surveys are likely to find artificially high percentages for repeal.

So here's a suggestion: All Web sites that report polling averages should confine themselves to samples that include both landline and cell-only users. If they include the landline-only surveys, they will be knowingly distorting their findings. If we are going to give so much attention to poll findings, we might as well be sure that the numbers are as close to right as we can get them.