The Food Demand Survey has been conducted nationwide and monthly since May of 2013. In November of 2014, two states - Colorado and Oregon - held widely publicized votes on mandatory GMO labeling.
These data allow us to calculate a so-called difference-in-difference estimate. That is - were people in CA and OR more concerned about GMOs than people in the rest of the country (this is the first difference) and how did this gap change during and after all the publicity surrounding the vote (this is the second and third difference)?
Apparently there was no effect. The graph below shows, as compared to people in other states where there were no votes, there was actually a small increase in concern for GMOs in CO and OR in the months during the vote ...which then fell back down to pre-vote levels after the vote.
So, despite evidence that the vote initiative on mandatory labeling led to an increase in awareness of GMOs in the news, it did not substantively affect concern about GMOs one way or the other.
The GLP aggregated and excerpted this article to reflect the diversity of news, opinion and analysis. Read full, original post: How Votes on GMO Labeling Change Concerns for GMO