Update: FiveThirtyEight.com’s Nate Silver, who studies and aggregates polls, has some thoughts here.
With SurveyUSA/KSTP set to release a new Minnesota gubernatorial poll today that excludes voters without landlines, I thought I’d pass along the Pew Research Center’s fresh update on the matter.
Good news for Dems: Landline-only polls are biased against you by several percentage points.
Good news for Republicans: You’re still going to stomp the Democrats.
Pew — which shares a pollster (Princeton Survey Research Associates) with the Star Tribune — surveyed 2,816 registered voters, a very big sample. When just landliners were polled, 46 percent favored Republicans, and 45 percent favored Democrats. Add in cell-phone-only voters (CPOs) and the Dems take the lead, 47-44.
Pew/PRSA also screened for likely voters, and here’s where the numbers get good for the GOP. The landliners go 53-41 for John Boehner’s crew, but when CPOs are added, it’s 50-43 GOP.
1. This is a generic Congressional ballot nationwide — it’s not specific to Minnesota.
2. This isn’t taking anybody’s temperature on a governor’s race.
3. A reminder: The Star Tribune does include CPOs; SurveyUSA, Rasmussen and MPR/Humphrey Institute polls don’t. Rasmussen released a poll last week showing DFLer Mark Dayton leading by 2 percentage points. Both the Strib and MPR/HHH have September polls showing Dayton with a 9- and 11-point lead, respectively. SurveyUSA’s last poll, on Sept. 12, showed Dayton up by two. (All results here.)
4. Pew’s number has bounced around a bit: a July-August survey showed no difference when CPOs were added in. But three of four surveys, including the most recent one, have.
5. Pew, curiously, doesn’t list a margin of sampling error for its latest survey.