A new poll showing the cannabis referendum on a knife-edge is good news for the pro-reform camp, an expert says.
The latest UMR polling, released by the Helen Clark Foundation and the New Zealand Drug Foundation on Tuesday, shows 49 percent in favour of legalising recreational use of the drug, and 45 percent opposed.
That's a lot closer than last week's Newshub-Reid Research polling, which had the no camp ahead 50-38.
American academic John Hudak, who studies cannabis policy, told The AM Show on Tuesday polls in the US ahead of similar referenda consistently underestimated support for reform.
"When we've looked at referenda in the United States, particularly the early referenda in the states of Colorado and Washington, it showed a very tight race between passage and not," he said.
"The polling that came out today looks a lot like the polling did in 2020 in Colorado and Washington - support being a hair ahead of opposed - but also coming down to the wire. Ultimately both of those states passed by significant margins - both of those states passed their referenda by about 10 percentage points, despite polling being narrower."
Colorado voted to legalise cannabis in 2012 by 55 percent to 45, and the state of Washington followed soon after, 56-44. The last poll before the vote in Colorado had 53 percent in favour - slightly less than the final result, but within the margin of error. A poll ahead of the Washington vote had 50 percent in favour - significantly below.
"When it comes to an issue that is socially divisive or competitive, some respondents to a poll are unwilling to tell a pollster that they hold a certain position - in some cases people who are in favour of reform might not be willing to say that to a pollster, but when they go in to cast a ballot, they are willing to vote in favour of it," said Hudak.
"Cannabis still has taboos attached to it - people see it as something negative, something that is harmful, something that is risky, something that other people do.
"A lot of that in the United States was led by a decades-long effort by the Government, and that of course spread around the world. People still have those taboos inside of them - it might make it so they're unwilling to speak publicly about their position."
Many non-smokers think they'll be labelled a stoner if they publicly voice support, he said. But the referenda in the US couldn't pass without the support of people who don't use it.
Nearly 600,000 adult Kiwis used cannabis recreationally in 2019, Ministry of Health figures show - about 15 percent.
"The reality is... that when these ballot initiatives, they're earning 55-60 percent of the vote; but we know 60 percent of the voters in those states are not cannabis users. So there are a lot of people who are in favour of the reform even if they will never participate in the reform."
Hudak said while it is possible the wording of a poll question can influence the result, the wording in both the UMR and Reid Research polls was identical - "Do you support the proposed Cannabis Legalisation and Control Bill?"
He said while it was natural to question poll results when they come from a survey funded by a group with a stake in the matter - both the Helen Clark Foundation and the New Zealand Drug Foundation are in favour of reform - there was no reason to be suspicious of Tuesday's results, saying campaigns need to know whether they're ahead or behind so they could adjust their strategies.
Voting in the referendum has begun, and ends on October 17.