A new poll in the special election for Oregon’s 1st district found Democrat Suzanne Bonamici and Republican Rob Cornilles with wide leads in their respective primaries.

Primary ballots are being mailed today in the vote-by-mail-only election. Voting ends Nov. 8, and the primary winners will face off Jan. 31.

The poll, conducted by SurveyUSA for KATU-TV in Portland, found Cornilles taking 66 percent in the GOP primary, with no other candidate receiving more than 7 percent and 20 percent undecided. On the Democratic side, Bonamici took 52 percent, followed by Brad Avakian with 14 percent and Brad Witt with 9 percent. One-fifth of voters were undecided.

The poll was conducted Oct. 17-20 using mostly autodial on home phones, but about one in 10 voters from both parties responded to the poll digitally on their smartphones. Of the 403 likely GOP primary voters polled, 8 percent responded to a questionnaire shown on their smartphone. Of the 522 likely Democratic primary voters polled, 13 percent responded on their smartphone. The GOP poll had a with a 4.7-point margin of error, while the Democratic poll had a 4.4-point margin of error.

The crosstabs displayed the differences between the smartphone and landline respondents. The percentage differences between the candidates were proportionally similar between the two groups, but there was a disproportionate number of undecided voters who responded by smartphone. Fifty-six percent of Republicans and 69 percent of Democrats shown the questionnaire on their smartphones were undecided.

Reached for comment, SurveyUSA editor Jay Leve said his polling firm has conducted about 70 different experiments since June 2010 on how best to reach those without a home phone.

“We would characterize it as a work in progress,” Leve said of this polling method. “Not necessarily yet as the winner, but a very productive and promising approach for reaching cellphone respondents and making sure the views of those not reachable by home phone are included.”