Data from Pew Research Center polling this year suggest that the bias from not including cell phones in surveys is as large as, and potentially even larger than, it was in 2008. It is now estimated that one-in-four households have only a cell phone and cannot be reached by a landline telephone. Failure to include this demographically disparate population in polls could skew results. The Pew Research Center for the People & the Press conducts surveys with samples of landline and cell phones, which allow for comparisons. In three of four election polls conducted since the spring of this year, estimates from the landline samples alone produced slightly more support for Republican candidates and less support for Democratic candidates, resulting in differences of four to six points in the margin. One poll showed no difference between the landline and combined samples. Read More