The Pew Research Center for the People and the Press has released an interesting new report addressing the effects of increasing cell phone use on the quality of telephone surveys. The concern has been that as more Americans rely more exclusively on cell phones (which are unreachable by traditional telephone survey methods), the representativeness of survey responses are declining significantly.
Pew used a survey of landlines compared with a survey they conducted of cell phone numbers. While they found some demographic differences between the two groups, particularly with regard to age, they noted that "When data from both samples are combined and weighted to match the U.S. population on key demographic measures, the results are virtually identical to those from the landline survey alone." Pollsters using traditional dialing methods have often argued that they can minimize the concerns about cell-phone-only households by weighting their samples accordingly. The Pew report provides support for this assertion:
"On key political measures such as presidential approval, Iraq policy, presidential primary voter preference, and party affiliation, respondents reached on cell phones hold attitudes that are very similar to those reached on landline telephones. Analysis of two separate nationwide studies shows that including interviews conducted by cell phone does not substantially change any key survey findings."
There is a lot of information in the Pew report, and it is a much read for those interested in survey research. Check out the full report here.