Which Pot Poll to Believe in Oregon?

legalize marijuanaWe have two recent polls on the marijuana ballot initiative in Oregon, Measure 91, and they diverge significantly from each other.

One poll came out yesterday. It was conducted by Elway Research for The Oregonian and KGW.  It found the measure losing, with 44 percent of likely voters planning to vote yes and 46 percent planning to vote no.

The other poll was released by SurveyUSA  for KATU-TV last week. It found 48 percent of likely voters supporting Measure 91 and only 37 percent opposed.

There are three big reasons why I’m inclined to put significantly more stock in the SurveyUSA poll and doubt this Elway poll. The first has to do with issues about the Elway poll’s turnout model. According to the Oregonian the poll assumes 70 percent of the electorate will be over the age of 50. That seems unlikely based on past elections and is very important given how much support for legalization correlates with age. By comparison the SurveyUSA poll puts this age groups share at only 58 percent.

The second reason is past performance. Elway’s marijuana legalization poll of Washington State at this same time two years ago was off. It found Initiative 502 leading only 48 percent yes to 44 percent no, but it ended up winning 55.5 percent to 44.5 percent. By comparison, SuveryUSA’s final poll of Initiative 502 was very close to the final result.

Finally, the big reason to doubt the Elway poll is all the other polls so far. For example the poll for OPB and Fox 12 earlier this month found Measure 91 winning 52 percent yes to 41 percent no. That margin is effectively identical to the SuveryUSA poll. That is why when possible we try to look at the averaging of multiple polls because there is always the chance any one can be an outlier.

Of course in a week we will know which pollster is more accurate and if Measure 91 does lose I will re-evaluate my opinion of the pollsters involved. For now, though, I would put my bets on this SurveyUSA poll.

Which Pot Poll to Believe in Oregon?

legalize marijuanaWe have two recent polls on the marijuana ballot initiative in Oregon, Measure 91, and they diverge significantly from each other.

One poll came out yesterday. It was conducted by Elway Research for The Oregonian and KGW.  It found the measure losing, with 44 percent of likely voters planning to vote yes and 46 percent planning to vote no.

The other poll was released by SurveyUSA  for KATU-TV last week. It found 48 percent of likely voters supporting Measure 91 and only 37 percent opposed.

There are three big reasons why I’m inclined to put significantly more stock in the SurveyUSA poll and doubt this Elway poll. The first has to do with issues about the Elway poll’s turnout model. According to the Oregonian the poll assumes 70 percent of the electorate will be over the age of 50. That seems unlikely based on past elections and is very important given how much support for legalization correlates with age. By comparison the SurveyUSA poll puts this age groups share at only 58 percent.

The second reason is past performance. Elway’s marijuana legalization poll of Washington State at this same time two years ago was off. It found Initiative 502 leading only 48 percent yes to 44 percent no, but it ended up winning 55.5 percent to 44.5 percent. By comparison, SuveryUSA’s final poll of Initiative 502 was very close to the final result.

Finally, the big reason to doubt the Elway poll is all the other polls so far. For example the poll for OPB and Fox 12 earlier this month found Measure 91 winning 52 percent yes to 41 percent no. That margin is effectively identical to the SuveryUSA poll. That is why when possible we try to look at the averaging of multiple polls because there is always the chance any one can be an outlier.

Of course in a week we will know which pollster is more accurate and if Measure 91 does lose I will re-evaluate my opinion of the pollsters involved. For now, though, I would put my bets on this SurveyUSA poll. (more…)