Missing Democratic Voters

Last week, I tweeted the following shocker: "If you exclude cell-only voters -- Democratic voters -- from polls, the numbers will look better for the GOP." The context was a McClatchy poll that showed Democrats and Republicans tied among voters with landlines, but Democrats leading by a staggering 59 percent to 33 percent margin among cell-only voters.

Today Nate Silver delved a bit deeper into the cell-only voter numbers and found the trend wasn't limited to McClatchy polling, or Pew polling discussed here.

The polls that were conducted without cellphones showed Republicans ahead by an average of 9.3 points; those with them showed a smaller, 4.8-point advantage. That’s a difference of 4 or 5 points (and one which is statistically significant at the 95 percent confidence threshold), which is about of the same magnitude that Pew identified.

As Silver said, this doesn't mean that Democrats should bank on performing as much as 5 percentage points better on election day than polls currently project. That said, a whole lot of polling -- especially statewide and district-level polling -- has not included cell-only voters. If these voters do show up -- and that remains an "if," considering that they are generally considered to be low-propensity voters -- the results could look very different than many are expecting.