The addition of cell phones in Pew Research Center election surveys had at most a modest effect on estimates of candidate support in individual surveys, but when looked at in the aggregate clear patterns emerge resulting in slightly more support for Obama and slightly less for McCain.
2008 Methodology Reports
Though by no means a perfect instrument, polls make it possible for more opinions, held by a broader and more representative range of citizens, to be known to the government and thus, potentially, heeded.
As shown in our election summary release, including cell phone interviews results in slightly more support for Obama and slightly less for McCain.
This is the first study documenting how the overall estimate of voter presidential preference is modestly affected by whether or not the cell phone respondents are included.
The Pew Research Center has been studying the challenge to survey research posed by the growing number of wireless-only households. Here's a summary of its latest findings.
A ‘Brute Force’ Estimation of the Residence Rate for Undetermined Telephone Numbers in an RDD Survey
Public Opinion Quarterly 72:28-39 (2008)
This paper discusses ''e'' the proportion of unresolved telephone numbers that are, in fact, eligible for the survey.
This study finds that respondents reached on cell phones hold attitudes very similar to those reached on landline telephones on key political measures such as presidential approval, Iraq policy, vote preference and party affiliation.