Yes on Proposition 19 has just released a set of internal numbers for polling they conducted last week, which compared responses given to live interviewers versus automated telephone polling. Interestingly, there is a huge divide between the level of support expressed for Prop 19 with the two methodologies. They find that if an individual is responding only to a computer program, they are much more likely to express support for Prop 19.
Yes on Prop 19 (10/13-14)
Live interviews (with leaners):
I have previously speculated that Prop 19 might be do better in polls conducted without live interviewers. There is still a stigma in many communities attached to marijuana use which could make some voters embarrassed to tell a stranger over the phone they plan to vote for legalization.
PPP and SurveyUSA ,which use automatic interviews, have consistently shown greater support for the initiative. We have seen recently that SurveyUSA, using mostly automated interviews, found the measure winning 48-44 while PPIC, using live interviews, had it losing 44-49.
This internal polling from the campaign confirms not only that interviewees seem to be lying to live pollsters, but also that this effect is quite pronounced among certain groups — particularly young voters. In live interviews, voters under 30 support the measure only 49-37. But in the automatic interviews, young voters support Prop 19 by an enormous 73-22 margin.
In general, ballot measures tend to be very difficult to poll. The social and legal issues associated with marijuana use makes things even more complicated. The ability to do a straight-up comparison of the results of automated versus live interview polling helps explain some of the wild discrepancies we’ve been seeing in Prop 19 polling of late. The results provide very positive news for supporters of the measure, and if they are correct, Prop 19 will likely become law.
Yet the results also a reminder that we should treat all polling on this measure with a healthy dose of skepticism, given how hard it appears to be to get accurate information on how people truly intend to vote come election day.