Yes, but not much:
The latest Pew Research Center national survey, conducted June 18-29 with a sample of 2,004 adults including 503 on a cell phone, finds that the overall estimate of voter presidential preference is modestly affected by whether or not the cell phone respondents are included. Barack Obama holds a 48% to 40% lead in the sample that includes cell phones, and a 46% to 41% advantage in the landline sample.
Next Page