Explaining big gaps in this year's election polls

The key is how pollsters are screening for likely voters, a tricky science at best.

The key is how pollsters are screening for likely voters, a tricky science at best.

I believe in polling. I think most polls done by reputable firms are accurate.  I don’t believe pollsters release bogus numbers to try and influence elections, and I have little patience for partisans who question numbers from reliable pollsters just because they don’t like the results.

So the widely divergent poll results we have seen over the past week or so have both intrigued and confused me.  In Washington's 3rd and 9th Congressional Districts, SurveyUSA’s results differ dramatically from polls released by the Democratic campaigns.  Likewise, in the Senate race, SurveyUSA shows the race much closer than do other pollsters. 

Private polls done by the Republican campaigns show results close to the SurveyUSA numbers. 

What’s going on here?  How, for instance, can one poll show Congressman Adam Smith in a tight race, and another show him ahead by over 19 percentage points

Over the past week I have spoken to pollsters and consultants from both parties.  All agree that this year it is unusually difficult to screen for likely voters, and that the two parties are approaching that differently.  It appears Democratic pollsters are looking at voter history, while Republican pollsters and SurveyUSA are measuring voter enthusiasm.  The theory is that many Republicans voters who were discouraged and failed to vote in 2006 and 2008 are energized this year and will turn out.  Democratic pollsters disagree and are looking more at voter history.  Hence the differences we are seeing in the polling results.

Who is right?  The only way to measure a pollster’s accuracy is to compare their previous final polls to actual election results.  Democrats in Washington State are skeptical of SurveyUSA right now, but that firm has been as accurate as any other public pollster in recent years.

Other than movement in the Rossi-Murray race, I have seen nothing that leads me to believe the general narrative has changed.  Republicans have a healthy lead in the national generic ballot poll, and appear poised to take the majority in the U.S. House, and gain five to seven seats in the U.S. Senate.

Here at home, the Senate race is close, with Sen. Murray perhaps slightly ahead.  The Rossi campaign has increased its TV advertising and shifted to a tougher message.  It still appears likely that Republican Jaime Herrera will win the 3rd Congressional District, and the John Koster-vs.-Rick Larsen race in the 2nd CD will be the closest congressional race in the state.  Republicans will make major gains in the legislature.

Five weeks to go and the story hasn’t changed since January: It looks like the pendulum is going to swing back to the right.


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About the Authors & Contributors

Chris Vance

Chris Vance

Chris Vance, a former Republican party chairman, is a senior fellow at the Niskanen Center.