The Yes on 37 and No on 37 campaigns each report drastically different estimates regarding California Proposition 37’s potential effects on annual household food costs. The discrepancy is largely a result of differing assumptions on supply chain reactions.

The report, publicized on the Yes on 37 campaign website, focuses almost entirely on how labeling will change costs to food producers and distributors, making the assumption that all or most producers will choose to label their product as “Genetically Engineered.” According to author Joanna Shepherd-Bailey, a professor at the Emory School of Law, the total cost of labeling changes would result in a negligible $1.37 increase in annual food costs.

The opposition’s analysis focuses on what it claims to be a more likely outcome: food growers making wide-spread conversions to non-Genetically Engineered (GE) and Certified Organic crops. This would apparently result in price hikes for consumers, raising the cost of grocery bills by up to 400 dollars annually for each California household. The report only briefly considers the labeling scenario, estimating costs to be between three and eight million dollars for food distributors.

Most large-scale agricultural producers, farmer coalitions and farm bureaus currently oppose California Prop 37, while organic farmers and producers tend to be in favor of the bill. (Organic products and produce are exempt under Prop 37 because Certified Organic produce already cannot include GE crops). However, not all agricultural supporters of Prop 37 come from Certified Organic farms.

Bob Cannard, co-owner of Green String Farm in Petaluma, California, is strongly in favor of Prop 37. “I don’t see how it would increase costs ,” says Cannard, whose farm does not use pesticides but instead works with the ecological system as a whole to produce nutritious food. In fact, Cannard believes that continuing to grow GE crops will increase food prices over time.

Costly or not, Californians appear to be strongly in favor of Prop 37. A recent poll sponsored by the LA Times and the University of Southern California found that 61 percent of Californians support Proposition 37, even after being made aware of the potential increased food costs associated with the bill.