Now that the election is over and almost all of the votes have been counted, it is worth examining how accurate the polling on marijuana legalization was this cycle. Knowing how the polling throughout the campaign compares to the final results is important for determining when and in what states similar initiatives should be tried going forward.

Just as with Proposition 19 in California last cycle, the final set of polls in both Washington State and Colorado proved to be very useful. In Washington State the polls near perfectly predicted the percent of the vote Initiative 502 would get. While in Colorado the final polls slightly understated Amendment 64 support.

Colorado SurveyUSA (10/28-31) PPP (11/3-4) Actual Vote
Yes 50 52 54.9
No 44 44 45.1
Washington SurveyUSA (10/28-31) PPP (11/1-3) Washington Poll (10/18-31) Actual Vote
Yes 56 53 55.4 55.5
No 37 44 37.6 44.5

Overall the actual yes vote on marijuana legalization initiatives tended to slightly exceed the level of support found in final polls. Going forward the lesson seems to be that as long as a marijuana legalization initiative is polling at just around 50 percent support before the election, it is likely to pass.

The one thing that made the polling in this election different from 2010 is that the polls remained remarkably stable throughout the campaign. In 2010, Prop 19 was ahead in the polling during the summer but support collapsed in the final month. By comparison support for Initiative 502 and Amendment 64 remained almost unchanged with no drop at the end. SurveyUSA’s first poll on I-502 back in July found 55 percent of voters planning to support it, and every poll they conducted consistently found support between 55%-57%. Similarly, all of PPP polling since August consistently had Amendment 64 winning by roughly eight to nine points.

This past election basically proves that the 2010 Prop 19 last minute drop in the polls was due only to issues specifically related to that initiative/campaign; it wasn’t some natural tendency for voters get cold feet about marijuana legalization initiatives at the last minute.

The lesson for potential future efforts seems to be that as long as the polling roughly a year out from the election shows just over 50 percent support for the general idea of legalizing marijuana, a well written initiative backed by a good campaign stands a solid chance of being approved. There are several states that should likely meet this criterion in 2014 or 2016.