The folks over at FiveThirtyEight.com have done an in depth analysis of polling and cellphones. As anyone who teaches at college can tell you, most students don’t have a landline. The fact that pollsters have only just started polling cellphone users creates some pretty startling statistics. The results give Obama a 2.8 point bump.
The difference is statistically significant at the 95 percent confidence level. Perhaps not coincidentally, Gallup, Pew and ABC/WaPo have each found a cellphone effect of between 1-3 points when they have conducted experiments involving polling with and without a cellphone supplement.
A difference of 2-3 points may not be a big deal in certain survey applications such as market research, but in polling a tight presidential race it makes a big difference. If I re-run today’s numbers but add 2.2 points to Obama’s margin in each non-cellphone poll, his win percentage shoots up from 71.5 percent to 78.5 percent, and he goes from 303.1 electoral votes to 318.5