By Jacob Sullum
Six surveys have asked California voters about Proposition 19 since the marijuana legalization initiative officially qualified for the ballot in March. Three of them show the measure losing narrowly, while the other three
(including the most recent one) show it winning by at least 10 points. Poll maven Nate Silver notes that the former three surveys were conducted by humans, while the latter three were conducted by "robopoll" machines.
Two recent national surveys show a similar pattern. Silver speculates that reluctance to endorse a controversial position in a conversation with a live person, especially when that position may be seen as reflecting one's own stigmatized habits, may explain the discrepancy between the two types of polls. If so, that's good news for the proposition's supporters, since voters will be dealing with machines at the polls this fall.
I discussed Prop. 19 in my column this week.