Are Organic and Non-GMO Labels Substitutes or Complements?

For the first time today, I saw the following label on a packaged food.


In a way, the label seems a little odd.  An organic seal on a product should already convey to consumers that the ingredients came from a process that excluded GMOs.  However, the very presence of the label suggests many consumers may not be aware of this fact.  

I have a paper with Brandon McFadden forthcoming in journal Applied Economic Perspectives and Policy (sorry, I don't yet have a link to the paper on the AEPP's website; I'll pass it along when I get the link and discuss the whole paper in more detail).  In the paper we delve into this issue and others.  Here's part of the motivation.  

It appears that organic organizations are concerned that consumers perceive non-GM and organic labels to be substitutes. Although many organic food companies supported the general idea of mandatory labeling, now that the policy has passed, organic producers have expressed concern that non-GM verification may be perceived as a substitute for the more expensive and encompassing organic certification. For examples, California Certified Organic Farmers (CCOF) initiated a campaign “Organic is Non-GMO and More” to highlight the differences in the two claims, and the Organic Trade Association (OTA) emphasizes, “Organic = Non-GMO…and so much more!!” Despite these concerns, little is known about the extent to which the two most common non-GM labels, USDA Organic and Non-GMO Project, are demand substitutes or complements. Whether the labels are demand substitutes or complements can be determined, in our context, by investigating whether WTP [willingness-to-pay] is supra- or sub-additive when the labels are combined. If the premium for displaying both labels is less than the sum of individual premiums for each label, then the two labels must be providing some of the same underlying characteristics of value to the consumer and implies the two labels are substitutes. By contrast, if the premium for displaying both labels is greater than the sum of individual premiums, then the two labels are complements and provide more value when provided together.

We ultimately find that products with the organic seal and products with the non-GMO verified seal are indeed demand substitutes.  Here's one paragraph related to those results:

For apples, the results revealed large and statistically significant substitution effects for Non-GMO and USDA Organic labels. In fact, results indicated that the two are almost perfect substitutes as WTP [willingness-to-pay] premiums for apples with both Non-GMO and USDA Organic labels roughly the same as WTP premiums for apples that display only one label. This result is made obvious by the third column of results. The WTP premium for apples with the Non-GMO label only (vs text label) is $0.446, the WTP premium for apples with the organic label only (vs text label) was $0.474, and the WTP premium for apples with both Non-GMO and USDA Organic labels was $0.446+$0.447-$0.461=$0.432, which is actually lower than when either label is present in isolation.

Because it is more costly to be organic than non-GMO (since the latter is a subset of the former), it is easy to see why many food companies would want to add the additional label that "Organic is non-GMO and more".