Economics, Evidence, and High Causal Density

How do we form our beliefs about the solutions to societies most complex problems? Do we trust data? Theory? Both? What does it mean to base policy on science and evidence?

According to Manski:

"Social scientists and policymakers alike seem driven to draw sharp conclusions, even when these can be generated only by imposing much stronger assumptions than can be defended. We need to develop a greater tolerance for ambiguity. We must face up to the fact that we cannot answer all of the questions that we ask."

I think Russ Roberts puts it well in his EconTalk Episode with Noah Smith:

"Can you think of a study that was so decisively performed in terms of the crossing of t's and dotting of i's that the identification and all the econometric challenges were met with such impressiveness that people on the other side of the debate had to throw up their hands and say, 'Well, I guess I was wrong. I've got to change my view.' Because I can't think of one. I can't think of one. And if that's true, then I would suggest that economics has some serious problems in claiming it's a science."

When it comes to evidence there are lots of challenges. For the most part, in economics and the social sciences it's often impossible to implement randomized controlled trials to identify treatment effects related to policy changes. For the most part we have to leverage observational data using quasi-experimental designs. The challenge for both approaches as Jim Manzi discusses in his book ''Uncontrolled: The Surprising Payoff of Trial-and-Error for Business, Politics, and Society'  is the issue of 'high causal density.'

In an environment of high causal density "the number of causes of variation in outcomes is enormous, and each has significant potential effects compared with those of the potential cause of interest. We don't know enough to list each of them and hold them constant, but if we randomly assign patients to the test and control groups, then these hidden conditionals won't confound our estimate of treatment causality."

Unfortunately in the social sciences, causal pathways are extremely complex. There are always hidden conditionals we may not be able to measure or don't have sufficient knowledge to even consider. Given that hidden conditionals are always present, a well entrenched proponent of a given policy can always find a reason to explain why it has failed to prove itself out in the face of evidence.

But Jim does more than offer criticisms of theory and methods. He introduces the concept of 'Liberty as Means.'  Embracing the concepts of evolutionary economics, he promotes a flexible system of government that sounds a lot like federalism. As he discusses, the mistake we often see from both the right and the left is enforcement of social norms at the national level vs. fostering numerous experiments at the local level.

While economic theory and applied econometrics are useful and powerful tools for policy analysis,  these tools will not necessarily help provide clear cut  always defensible evidence to improve public policy. These methods will never discover a 'Polio vaccine' for policy. It is in fact their shortcomings that provide the strongest argument for our constitutional republic and federalism that our founders envisioned.

Reference: Uncontrolled: The Surprising Payoff of Trial-and-Error for Business, Politics, and Society, by Jim Manzi https://www.amazon.com/Uncontrolled-Surprising-Trial---Error-Business/dp/046502324X/ 

See also: EconTalk: Manzi on Knowledge, Policy, and Uncontrolled

Tariffs and the Corn-Soybean Industrial Complex

Recent trade policy talks and tariffs imposed by the Trump administration have had an impact on soybean prices (see: Trump's And China's Tariffs Could Do Permanent Damage To Soybean Farmers). As a result, one time payments have been proposed to help farmers but going into the next marketing year nothing is on the table.

An interesting observation is that some folks typically critical of the Trump administration have found this to be a silver lining. Their story goes something like this: Not all that is Trump is bad because hopefully he's breaking down the corn-soybean industrial complex. The trade war is overpowering the effects of the subsidies that usually keep the machine churning out the kinds of crops that are harming the planet and making us sick at the expense of more sustainable and healthy fruits and vegetables.

This isn't really new, its just another version of the same criticisms we often hear from the politically correct food activist crowd (i.e. the pro organic, pro-heirloom/nostalgic market,anti meat, anti-grain, anti-commodity anti-biotech agriculture folks)

Subsidies (primarily crop insurance) can impact marginal changes in the mix and total acres of corn and soybeans each year, but they are not a primary driver in the decision to grow those crops vs. vegetables etc. The difference has more to do with biology than policy.

Economist Jayson Lusk discusses the impacts of reducing or removing these subsidies: 

"complete removal of crop insurance subsidies to farmers would only increase the price of cereal and bakery products by 0.09% and increase the price of meat by 0.5%, and would also increase the price of fruits ad vegetables by 0.7%.  So, while these policies may be inefficient, regressive, and promote regulatory over-reach, their effects on food prices are tiny"

When we try to connect this to food consumption and the impacts on obesity, the evidence is very weak.

Alston (2010) found:

“Eliminating U.S. grain subsidies alone would lead to a small decrease in annual per capita caloric consumption—simulated to be 977 calories per adult per year, which would imply a 0.16% per year reduction in average body weight assuming 3,500 calories per pound. In contrast, removing all farm subsidies, including those provided indirectly by trade barriers, would lead to an increase in annual per capita consumption in the range of 200 to 1,900 calories—equivalent to an increase in body weight of 0.03% to 0.30%.”


The difference in prices between grains and vegetables won't change much with changes in subsidies and the impact on obesity is less than trivial. One reason commodities and grains are favored over other crops is they are more affordable, cost less to produce, and store much better. As Tamar Haspel notes in a previous Washington Post article:

"Factor in that corn delivers 15 million calories per acre to broccoli’s 2-ish million, and the cost to grow broccoli (25 cents per 100 calories) is 50 times larger than corn (half a cent per hundred calories). And that’s just the difference on the farm. After harvest, that broccoli needs to be refrigerated and transported to where it’s going before it spoils. Broccoli has nutrients that corn doesn’t, of course, so it’s a good thing that we eat some. But an all-vegetable, or mostly vegetable, diet is prohibitively expensive for most people"

At the end of the day, labeling the complex network of producers, scientists, retailers, merchandizers, processors, and traders involved in feeding a hungry global population as the 'corn-soybean industrial complex' may have dramatic appeal. But the biology and economics involved tell another story.

References:

Choices. 3rd Quarter 2010 | 25(3)
FARM POLICY AND OBESITY IN THE UNITED STATES
Julian M. Alston, Bradley J. Rickard, and Abigail M. Okrent
JEL Classifications: I18, Q18

Rational Irrationality and Satter's Hierarchy of Food Needs

In HIERARCHY, DISAGREEMENT, AND FOOD POLITICS food economist Jayson Lusk discusses Maslow's Hierarchy of Needs and a modification or application by Ellyn Satter. Satter conceptualizes a hierarchy of food needs. Basically the idea is that as society reaches more advanced levels of economic development and incomes rise, our preferences related to food change.

"Satter called the top of this pyramid "instrumental food" and she said such foods were consumed to "achieve a desired physical, cognitive, or spiritual outcome."  If we're talking about food satisfying a particular view of what I think of myself (I eat what I am) or food satisfying a "spiritual outcome", why would we expect you and I to agree on what is "best"?  In this sense, we might expect food consumption to be more politicized"

Another way of thinking about this is that high end food fads marketed by the likes of Chipotle and Whole Foods are 'normal goods' i.e. as incomes rise their consumption should increase. There is a reason why you only find certain food chains and grocery stores in areas where incomes are higher.

Satter notes: "These instrumental reasons may or may not be rational or supported by scientific inquiry."

This is not so different from the concept of 'rational irrationality' discussed in Brian Caplan's 'The Myth of the Rational Voter':

"...people have preferences over beliefs. Letting emotions or ideology corrupt our thinking is an easy way to satisfy such preferences...Worldviews are more a mental security blanket than a serious effort to understand the world."

This means that:

"Beliefs that are irrational from the standpoint of truth-seeking are rational from the standpoint of utility maximization."

And in application:

"Support for counterproductive policies and mistaken beliefs about how the world works normally come as a package. Rational irrationality emphasizes this link."

One of the main themes in the book is that this leads to systematic biases in voting behavior and policy. Particularly, these kinds of preferences create a gap between economic principles and policies supported by most economists vs. the general public. The authors note that this division probably is not unique to economics and they are correct. As Jayson Lusk notes, a few years ago research from the Pew Foundation identified a number of scientific issues for which there is a gap between views held by scientists and the public. 

So how does this play out? A colleague brought up a very important point. Rational irrationality implies that there are costs associated with irrational beliefs, and people are willing to hold on to certain world views given the costs are low. Since the costs associated with voting are much lower, and voters don't necessarily bear the full costs of their actions we would expect to see 'rational irrational' behavior more often in voting than we see with regard to food purchasing behavior. However, when we think about Satter's hierarchy the idea is that with increased incomes preferences for food become more abstract (related to politics, ideology, social status etc.). Consumers are willing to pay for that. However, for higher income consumers the share of food in the household budget is relatively small (Engel's Law). Hence the costs of 'irrationality' are minimal compared to what those costs would be for lower income consumers or at the bottom of Satter's hierarchy. This means that wealthier demographics and wealthier societies can afford to be 'rationally irrational' to some degree when it comes to actual food purchases as well as voting.

When you think about the opportunity this presents to food marketers in addition to special interest agendas like the non-GMO Project and US Right to Know combined with low cost voting and it’s a perfect storm.  As this influences food manufacturers and the regulatory environment, we begin to see an impact on food choices on the shelves. This impacts the way food is labeled, marketed, and perceived and the ingredients used or not used. This has impacts going all the way back the supply chain to the farm gate. These influences may come at the expense of more affordable options that may otherwise be produced with more efficient and sustainable technologies. This can exasperate issues related to food waste and food insecurity. Examples include Vermont's GMO labeling law, push back against new food technologies like the arctic apple, and the attempt in Brazil to ban glyphosate and related court cases here in the U.S.

Don't Throw Good Science Out With the Dirty COI Bathwater

There has been a lot of conversation lately regarding conflicts of interest in research. This recent tweet by Andrew Kniss resonated a lot with me:

Things I've learned recently about how to handle Conflicts of Interest:
1) if COI is not disclosed, dismiss the work as biased.
2) if the COI is disclosed, dismiss the work as biased.
3) if no COI exists, dismiss the work as biased because the author isn't being transparent.

— Andrew Kniss (@WyoWeeds) September 14, 2018

No doubt conflicts of interest are important to be aware of and understand. We definitely want to maintain the highest integrity with regard to science communication and research. However, it is important that COI 'labels' don't become the new 'free-from' label i.e. we don't want a conflict of interest to necessarily become conflated with bad science any more than we would want a GMO label to be conflated with unhealthy or unsustainable. We don't want COI to become the red herring for smear campaigns, political correctness, or a disincentive to doing good science.

About a year ago during one of his excellent talking biotech podcasts (specifically regarding the movie Food Evolution) Kevin Folta made an excellent point about COI and bias in research:

"I've trained for 30 years to be able to understand statistics and experimental design and interpretation...I'll decide based on the quality of the data and the experimental design....that's what we do."

COI involve a delicate balance. I think the recent controversy around COI highlights the importance for producers and communicators of science to get this right. There's also a challenge for consumers of science to know how to recognize good science without throwing it out with the COI bathwater.

CRISPR and Gene Editing Blueprint Analogy

There was a nice guest post on AgWeb recently titled:

Gene Editing: Building Better Blueprints, One Gene at a Time. 

I really like the blueprint analogy as a means to help people understand how gene editing is similar and different from other technologies. Many consumers that are skeptical of advances in food technology are comfortable with older technologies or don't realize the differences.

As Bob Reiter stated in the article:

"Now consider this: what if there was a defect in the blueprint for the house? If we followed those instructions anyway, the defect would be built into the house – which could later lead to structural problems, ranging from minor to catastrophic, depending on which part the defect involved."

Messing up the blueprint is what a lot of consumers are hesitant about when it comes to traditional recombinant DNA technologies (a.k.a. 'GMOs'). They are worried about unknown downstream structural problems and the impact that could have on human health. To put this in other terms, genomic disruptions. In response they advocate for more regulations, testing, and labeling of 'GMO' foods and many are calling for a similar framework for gene edited foods. And food manufacturers take advantage of the marketing opportunities created by these concerns. Ever heard of the non-GMO Project?

But the blueprint analogy is actually helpful here. As Bob explains, in college he was careful about designing the blueprint. If we think of gene editing like making careful targeted changes to the blueprint, USDA organic approved technologies (methods using radiation or chemical mutagens) are more like his intoxicated fraternity brothers sneaking in making random changes to his plans without him knowing. Perhaps they introduce really cool innovations! On the other hand, the roof might leak, the plumbing could drain backwards, or worse. To put it differently, the number of genomic disruptions are far greater and unknown.

You would think, if customers and regulators were concerned about Bob's targeted changes (maybe they would insist that someone from the county does an inspection before proceeding with the construction) they would really be worried about the changes brought about by his inebriated counterparts. However, if we analogize back to mutagenic conventional and organic food, they don't seem concerned at all. They have accepted a build it and see what happens later attitude. No testing. No labeling. (other than maybe that Butterfly food marketers like to stamp on everything from rock salt to water). Of course, from a scientific risk based perspective, there probably is not a reason for testing or labeling these foods....if consumers already understand and accept this that should be a step further down a path toward newer 'safer' technologies that promise so much more.

You can only take an analogy so far but I like Bob's.

See also: Organic Activists Realize Hypocrisy On Gene Editing and Biotech

References:

Batista R and others (2008). Microarray analyses reveal that plant mutagenesis may induce more transcriptomic changes than transgene insertion. Proceedings of the National Academy of Sciences of the United States of America 105(9): 3640–3645

Baudo MM, Lyons R, Powers S, Pastori GM, Edwards KJ, Holdsworth MJ, Shewry PR. (2006). Transgenesis has less impact on the transcriptome of wheat grain than conventional breeding. Plant Biotechnol J. 2006 Jul;4(4):369-80

The convergence of data science, genomics, and technology

This is a couple years old but just as relevant and inspiring:

"I believe the future of agriculture will be shaped by continued improvements in efficiency. By more effectively applying the advancements that have come from the green and biotech revolutions, we can continue to see yield increases across the world. We can use data science to drive agronomic practice improvements that enhance existing technologies, like advanced seed genetics. Data science technologies can build upon the yield potential already present in each seed by providing farmers with actionable insights they can use to drive efficiency improvements on their operations, getting the most out of every single plant." - Erik Andrejko, Director of Science, Head of Data Science at The Climate Corporation (2015)

From: https://climate.com/blog/applying-data-science-to-enhance-farming-practices

See also: Monoculture vs. the Convergence of Big Data and Genomics

The 'free-from' Nash equilibrium

Recently I was reading an article, "The big Washington food fight" in Politico discussing challenges of bringing diverse interests and perspectives on food issues under one roof through the Grocery Manufacturers Association. 

There are a couple things influencing my thinking about this. One is the idea that voters and consumers may have systemic biases in their knowledge and preferences in general and specifically about food and technology. The other thing is related to recent research showing a divergence between public perceptions and science driven by political leaning....a divergence that widens *with* more education and science knowledge (see http://www.pnas.org/content/114/36/9587 ).

So in this context, what does it mean to say 'the customer is always right' and how do you give the customer what they want, but do it with integrity? There seem to be two dominant approaches or paradigms followed by food companies for dealing with this. 

One approach is going all in with 'negative' advertising or 'free from' labeling regardless of scientific justification. This paradigm feigns or fakes transparency in the sense it acknowledges consumer preferences related to knowing 'what is in their food' but adds lots of confusion about substantial differences related to food safety and sustainability. The other paradigm takes a 'less is more' approach in terms of honest disclosure about these technologies.

A more generous interpretation of the first behavior is that these food retailers and manufacturers are cognizant of consumer preferences, and assume great deal of consumer ignorance. Take for instance consumers attempting to avoid gluten (reasons why merit a separate discussion). Retailers may assume consumers are extremely ignorant of the fact that gluten originates from wheat based ingredients. A number of food products (like apples, raisins, ground beef, potatoes, carrots etc.) generally would not possibly contain gluten unless they were highly processed or prepared using some wheat based ingredient. As an extreme example for illustrative purposes, we might imagine an uninformed consumer choosing between a bag of carrots and a loaf of bread. A manufacturer would feel they are helping the consumer simplify the decision by adding a 'gluten free' label to the bag of carrots. Additionally, if competitor brands don't have the label, they may risk losing a sale to the 'gluten free' labeled product if a large enough number of uninformed consumers are trying to avoid gluten. We end up with a Nash equilibrium strategy to employ 'free from'labels that really make no sense from a nutritional or scientific standpoint. Gluten is just one example, the logic easily carries over to a number of food products and ingredients (i.e. free-from labels related to added hormones in pork and poultry, GMO free tomatoes etc.)

Helping consumers avoid what they *think* or *perceive* to be harmful to themselves or the environment using this strategy may help increase or defend sales, but it does very little to truly educate consumers about food choices. It likely perpetuates ignorance and myths about food, nutrition, health, and sustainability. Worse, in some cases it may directly or indirectly lead to consumers actually choosing marginally less healthy or less sustainable products or technologies either directly or indirectly because of decreased viability of marketing alternatively sustainable foods (i.e. the loss of rBST from the milk supply).

Whichever paradigm becomes the most dominant (both in the marketplace and the ballot box) may ultimately influence the types of products we see on the shelves and reduce the potential for healthier and more environmentally sustainable solutions to challenging worldwide problems. Efforts to escape this less than optimal Nash equilibrium position could include restrictions limiting free from labels to only non-obvious food products but I am not sure this is a viable solution.

Sometimes people devise cooperative ways to escape from a Nash equilibrium without resorting to taxes or regulation. Nobel prize winning economist Elinor Ostrom's work speaks to this:

"Predictions that individuals will not devise, precommit to, and monitor their own rules to change the structure of interdependent situations so as to obtain joint benefits are not consistent with evidence that some individuals have overcome these problems, although others have not." - Governing the Commons: The Evolution of Institutions for Collective Action. By Elinor Ostrom

But how would this work? The recent backlash by the scientific community regarding StonyField Organic's portrayal of young girls in a Facebook video and the Peel Back the Label movement are two examples of social harassment costs or other monitoring behaviors within the industry that may give some hope. Will this continue or become a large enough force for change?

Why Study Plant Breeding and Genetics?

A really nice piece in the Huffington Post by Kevin Folta evangelizing about future careers in plant breeding (link).

I like the way he describes genetic markers and marker assisted selection:

"The trick is to use DNA-based landmarks that physically travel through generations in parallel with the trait of interest. A simple DNA test, much like those used in forensic science, tells a breeder if a seedling has a high likelihood of presenting a coveted trait upon maturation. These tests allow breeders new ways to identify the most relevant parent plants, and eliminate non-candidate offspring at the seedling stage, long before valuable time, labor, acreage, fertilizers, and water are invested."

When I was an undergraduate senior, we had a speaker working on their PhD from UC Davis visit WKU to discuss their work in quantitative genetics. That was the first time I realized that there was lots of opportunity and very exciting work that could be done outside the lab, as genetics and crop improvement can be as much a statistical and quantitative science as a lab science. In other words, not all of the cool jobs were being taken by PhDs in molecular biology. As Kevin states:

"While mastery of molecular biology techniques is not required, modern breeders need to be conversant in the technologies, and excited to integrate with collaborators. A modern breeder will have strong skills in statistics, and even computational prowess."

This sounds a lot like a data scientist with domain expertise in plant breeding and genetics. From this angle there seems to be tremendous opportunities with the convergence of big data and genomics. While I did not pursue a career in plant breeding, I have leveraged my quantitative training in agronomy including experimental design and statistical genetics blended with econometrics and programming to advance my career in healthcare data science.

Think about the combination of genomic markers, plant 'wearable' sensors, remote sensing, and other precision ag data sources. Very exciting work for all involved.

Dr. Folta is an excellent evangelist for crop genetic improvement and science communication.  I highly recommend checking out his podcast Talking Biotech where each week he or Dr. Paul Vincelli from the University of Kentucky discuss agricultural and medical biotechnology.

Related: QTL Analysis and Marker Assisted Selection 

Herbicide Resistance and GE Crops - Thinking like an economist

In a recent issue of Weed Science, Andrew Kniss investigates the relationship between herbicide resistance in weeds and adoption of genetically engineered crops.

There is a popular story with an anti-gmo theme that holds that genetically modified crops tolerant to roundup (glyphosate) herbicide have encouraged excessive levels of use. This has lead to a build up of roundup resistant weeds. In some sense, this paper may provide some evidence in favor of that story. However, I think there is a tendency among critics to extrapolate further that GMOs lead to higher levels of weed resistance (in general). The storyline does not make a distinction between weed resistance in general and specific resistance to roundup.

What this paper does indicate is that there are to some degree externality mitigating aspects of glyphosate tolerant crops. (not exactly but somewhat like the positive externalities we have seen with Bt crops). As stated in the abstract, "Increased glyphosate use in cotton and soybean largely displaced herbicides that are more likely to select for herbicide-resistant weeds, which at least partially mitigated the impact of reduced herbicide diversity....the evolution of new glyphosate-resistant weed species as a function of area sprayed has remained relatively low compared with several other commonly used herbicide SOAs."

This paper definitely provides data and evidence contrary to some of the popular stories condemning biotechnology. Stories that don't look at crop production from a more comprehensive systems based viewpoint miss these nuances. Hmmm....it appears that thinking like an economist (systematically considering intended and unintended consequences) has a lot to lend to the nuances of herbicide resistance.

More from the Abstract:

 "adoption of GE corn varieties did not reduce herbicide diversity, and therefore likely did not increase selection pressure for herbicide-resistant weeds in that crop. Adoption of GE herbicide-resistant varieties substantially reduced herbicide diversity in cotton and soybean. Increased glyphosate use in cotton and soybean largely displaced herbicides that are more likely to select for herbicide-resistant weeds, which at least partially mitigated the impact of reduced herbicide diversity. The overall rate of newly confirmed herbicide-resistant weed species to all herbicide sites of action (SOAs) has slowed in the United States since 2005. Although the number of glyphosate-resistant weeds has increased since 1998, the evolution of new glyphosate-resistant weed species as a function of area sprayed has remained relatively low compared with several other commonly used herbicide SOAs."

Link and Citation:

Kniss, A. (2017). Genetically Engineered Herbicide-Resistant Crops and Herbicide-Resistant Weed Evolution in the United States. Weed Science, 1-14. doi:10.1017/wsc.2017.70

https://www.cambridge.org/core/journals/weed-science/article/genetically-engineered-herbicideresistant-crops-and-herbicideresistant-weed-evolution-in-the-united-states/22B3B07F8EB980D2CFEEE3AA36B7B2C1

See also: 
Game Theoretic Analysis of Bt Resistance
Positive Externalities of Biotech Bt Traits on Non-Biotech Crops and Non Target Insects
Environmental and Health Effects of Bt Cotton
Choices Magazine - Herbicide Resistance

Environmental and Health Effects of Bt Cotton

Kouser, S., Qaim, M., Impact of Bt cotton on pesticide poisoning in smallholder agriculture: A panel data analysis,Ecol. Econ. (2011), doi:10.1016/j.ecolecon.2011.06.008

"While substantial research on the productivity and profit effects of Bt cotton has been carried out recently, the economic evaluation of positive and negative externalities has received much less attention. Here, we focus on farmer health impacts resulting from Bt-related changes in chemical pesticide use. Previous studies have documented that Bt cotton has reduced the problem of pesticide poisoning in developing countries, but they have failed to account for unobserved heterogeneity between technology adopters and non-adopters. We use unique panel survey data from India to estimate unbiased effects and their developments over time. Bt cotton has reduced pesticide applications by 50%, with the largest reductions of 70% occurring in the most toxic types of chemicals. Results of fixed-effects Poisson models confirm that Bt has notably reduced the incidence of acute pesticide poisoning among cotton growers. These effects have become more pronounced with increasing technology adoption rates. Bt cotton now helps to avoid several million cases of pesticide poisoning in India every year, which also entails sizeable health cost savings." 

The Challenging Tradeoff of Weighing Biased Consumer Preferences Against Marketing Food with Integrity

Recently I was reading an artcile, "The big Washington food fight" in Politico discussing challenges facing bringing diverse interests and perspectives on food issues under one roof through the Grocery Manufacturers association.

There are a couple things influencing my thinking about this.....the idea that voters and consumers may have systemic biases in their knowledge and preferences in general and specifically about food and technology. The other thing is  related to recent research showing a divergence between public perception of science driven by political leaning....a divergence that widens *with* more education and science knowledge (see http://www.pnas.org/content/114/36/9587 ).

This research was not directly related to food except for genetically engineered food . Biotech related effects were not significant in this paper, but as the article noted the data is from 2006 and perhaps biotech was not nearly as politicized or polarized as it would be reflected in more recent data.

So in this context, what does it mean to say 'the customer is always right' and how do you give the customer what they want?

For instance, sustainable food seems to be high on the list of priorities. However, there are plenty of cases where the most sustainable technology is completely rejected by some segments. I'm thinking here of rBST, various aspects of biotechnology, even processing mechanics like finely textured beef. These are all examples where scientifically, you can produce more food using fewer resources and have a lower carbon footprint.

There seem to be two dominant approaches or paradigms by food companies for dealing with this.

One approach is going all in with the 'negative' or 'free from' labeling regardless of science. This paradigm feigns or fakes transparency in the sense it acknowledges consumer preferences related to knowing 'what is in their food' but adds lots of confusion about substantial differences related to food safety and sustainability. This group is more likely to engage in negative advertising (think Chipotle) and lobbying for regulations related to food labeling requirements (think Vermont). The other paradigm takes a 'less is more' approach in terms of honest disclosure about these technologies.

Production agriculture is caught in the middle. Whichever paradigm becomes the most dominant (both in the marketplace and the ballot box) I fear will determine the fate of the kinds of crops farmers grow and technologies they have access too, types of products we see on the shelves, and the potential for healthier and more environmentally sustainable solutions to challenging worldwide problems.

See also: Food with Integrity is Catching On

Polarization of Controversial Science and Limitations of Science Literacy

I recently reviewed a PNAS article titled "Individuals with greater science literacy and education have more polarized beliefs on controversial science topics". This was interesting along a couple of dimensions.

For one this is similar to research I was working on during my masters degree examining interrelationships between religous, science, and other beliefs and perceptions of genetically engineered foods. However this work had much better data.

The primary finding was that when it comes to certain beliefs about things like climate change, stem cell research, or evolution there are differences influenced largely by politics or religion. This polarization is actually increased as levels of education and science literacy are raised - "Individuals with greater education, science education, and science literacy display more polarized beliefs on these issues."

The authors looked at these effects in relation to genetically modified foods, but results were non-significant. This may be explained by the fact that the data source was ten years old (2006) and perhaps this issue had not become quite as polarized in a political sense like current data may suggest. This begs the question or the hypothesis proposed in the conclusion that "Understanding these mechanisms can guide science communication so that the evidence gets through before it no longer matters" i.e. perhaps before it becomes polarized by political priors.

This is really significant in an age where science literacy is a concern (right that's one reason we just had a march for science). This will ultimately influence the types of products we see on the shelves and the potential for healthier and more environmentally sustainable solutions to challenging worldwide problems.

From an econometric sense,  the polarization was captured in a quantitative sense via interaction terms in logistic regression. Predicted or fitted values were used to plot and visualize the interactions, sidestepping the hassle of attempting to discuss or interpret the estimates from the interaction terms in a statistical sense. Output was provided in the paper and an appendix.

I also would be interested to know more about any related work that may be looking at some of these factors as latent constructs in a structural equation context. 

See also: Voter Irrationality and Systematic Bias

Endogenous Growth Models and Stagnation in Agricultural Innovation

See also: Ideas and Research Productivity in Agriculture 

From: Big Ideas Are Getting Harder to Find - Stanford Business Insights:

"big ideas are getting harder and harder to find, and innovations have become increasingly massive and costly endeavors, according to new research from economists at the Stanford Institute for Economic Policy Research. As a result, tremendous continual increases in research and development will be needed to sustain even today’s low rate of economic growth." 

One of the key equations in the paper relates the number of researchers working in an area to the number of new ideas: research productivity = (A*/A)/S(t) = # new ideas / # researchers One particular area they looked at was with productivity in agriculture, measuring ideas as crop yields.

 “For instance, to measure productivity in agriculture, the study’s co-authors used crop yields of corn, soybeans, wheat and cotton and compared them against research expenditures directed at improving yields, including cross-breeding, bioengineering, crop protection and maintenance....On average, research productivity in agriculture fell by about 4% to 6% per year, the study found....Research productivity is simply the ratio of average yield growth divided by the number of researchers." 

They were careful to tease out research related to non-yield related traits. However, is 'yield' always the best way to measure productivity? Maybe it is a good proxy, but it looks like their data really starts in the 60's....about the time when corn seed was being transitioned away from double cross to single cross hybrids, which were more uniform and higher yielding. In terms of having a large marginal impact on yield, that seems like it could be a tough act to follow, even 40+ years later (its not like we will rediscover hybrid vigor or heterosis) no matter how many PhD's we throw at increasing yield. Other developments in crop improvement may in fact be inflating the denominator in the equation above. The convergence of big data and genomics has opened the door to numerous potential lines of research related to crop improvement, that although may only marginally impact yield provide other significant technological benefits to growers, consumers, and the environment. This would be important, even if yield were constant.

Advances in big data and genomics may have resulted in many more possible needles to search for in a much greater number of haystacks than before. Each crop has a different genome and a seemingly infinite number of biochemical pathways that could be of interest. Then there is the micro-biome and who knows what is next. We just need way more researchers than before.

 I'm not sure how much this applies in other fields, and in some ways this could be making the authors' point....look at all the lines and directions of research and scientists pursuing them vs. actual improvements in crop yields. But again, even if yield were constant, for every bushel of corn/soy produced today, how much have we improved with regard to CO2 reduction, energy use, erosion/leaching, reduction in toxic chemical exposure (thanks largely to roundup and Bt traits), and biodiversity (in terms of non-pest targets)?

Yield just seems to be one outcome among many of importance to creating sustainable development in the agriculture space (although it is important enough to sustainability that we certainly would not want to revert back to older technologies, genetics, and chemistries as some have argued). It would be interesting to see this modeled with traits or variety patents or total hybrids as a measure of new ideas.

References:

Are Ideas Getting Harder to Find? By Nicholas A. Bloom, Charles I. Jones, John Van Reenen, Michael Webb. September 2017Working Paper No. 3592

Modern Corn and Soybean Production. Rober G. Hoeft, Emerson D. Nafziger, Richard R. Johnson, and Samuel R. Aldrich. MCSP. First Edition. 2000.

Environmental impacts of genetically modified (GM) crop use 1996–2015: Impacts on pesticide use and carbon emissions. Graham Brookes & Peter Barfoot. GM Crops & Food Vol. 8 Iss.2, 2017 Genetically Engineered Crops: Has Adoption Reduced Pesticide Use?

Agricultural Outlook ERS/USDA Aug 2000 Greenhouse gas mitigation by agricultural intensification Jennifer A. Burneya,Steven J. Davisc, and David B. Lobella.PNAS June 29, 2010 vol. 107 no. 26 12052-12057

Voter Irrationality and Systematic Bias: Applications in Food and Biotechnology

In the Myth of the Rational Voter: Why Democracies Choose Bad Policies, Bryan Kaplan discusses issues related to the median voter theorem and systematic biases by voters.

One interesting concept he discusses is the miracle of aggregation. According to the miracle of aggregation democracies can make decisions as if all were well informed. If we assume that less informed voters make random mistakes,  errors will cancel and the votes that matter will be the informed ones. The well informed median voter determines the outcome.

This all breaks down if the most informed voters make systematic mistakes. In that case the median preference becomes biased away from the optimal policy. But why would well informed voters make systematic mistakes?

Sometimes our values and views are part of who we are. Believing certain things gives people higher levels of utility. They let preferences drive beliefs over evidence. To entertain information or evidence to the contrary would upset preferences and lower utility. To quote Caplan:

"letting emotions or ideology corrupt thinking is an easy way to satisfy such preferences"

He also quotes Lebon:

"the masses have never thirsted after the truth, they turn aside from evidence that is not to their taste...whoever can supply them with illusions is easily their master; whoever attempts to destroy their illusions is always their victim"

This idea of preferences driving beliefs explains a lot. For instance, the election of demagogues. There are clear benefits to be reaped in customizing political platforms and media content that feeds into the preferences of these different segments of the population. The media capitalizes on that at the expense of actually informing the electorate. So do politicians and pundits.

This also may explain the explosion of growth in organic, natural, hormone free and other niche food markets.  Or the popular support for GMO labeling initiatives despite the science behind both safety and environmental benefits of biotechnology.

All of these are cases where acceptance of scientific evidence should potentially change opinions and behavior as it relates to food and agriculture. However to change those opinions and choices would be to drastically upset the preferences of a number of consumers. This makes it hard for those in agriculture and science communication trying to help the public navigate the complex world of modern agriculture. It also makes it hard for companies, wanting to do the right thing, to make a stand for science (i.e. by not going down the non-GMO/hormone/gluten free negative labeling route).

For instance, what if a t-shirt manufacturer wanted to promote the use of Bt cotton in their products on the basis of a reduction in use of toxic pesticides and improved insect biodiversity? Or what if a food company wanted to promote their dairy products for having a lower carbon footprint due to rBST? Taking this position would likely upset the illusions and preferences held dearly by many consumers. Noone wants to become 'their victim' to borrow from Lebon. Just ask Monsanto or BPI, the company behind finely textured beef. (however ABC eventually paid a price for feeding the masses the pink slime 'illusion'). In response, we don't see these kinds of promotions, and to the contrary we actually see companies removing these technologies from their product lines (and advertising the fact!).

Due to systematic bias in relation to food and technology, the median of voters' preference distribution will be biased toward more restrictive regulations than is scientifically appropriate. This will influence the types of products we see on the shelves and the potential for healthier and more environmentally sustainable solutions to challenging worldwide problems.

References:

The Myth of the Rational Voter: Why Democracies Choose Bad Policies, Bryan Kaplan

The Crowd: A Study of the Popular Mind.  Gustave Le Bon.

A Meta-Analysis of Effects of Bt Cotton and Maize on Nontarget Invertebrates.Michelle Marvier, Chanel McCreedy, James Regetz, Peter Kareiva Science 8 June 2007: Vol. 316. no. 5830, pp. 1475 – 1477

Areawide Suppression of European Corn Borer with Bt Maize Reaps Savings to Non-Bt Maize Growers. Science 8 October 2010:Vol. 330. no. 6001, pp. 222 - 225 DOI: 10.1126/science.1190242W. D. Hutchison,1,* E. C. Burkness,1 P. D. Mitchell,2 R. D. Moon,1 T. W. Leslie,3 S. J. Fleischer,4 M. Abrahamson,5 K. L. Hamilton,6 K. L. Steffey,7, M. E. Gray,7 R. L. Hellmich,8 L. V. Kaster,9 T. E. Hunt,10 R. J. Wright,11 K. Pecinovsky,12 T. L. Rabaey,13 B. R. Flood,14 E. S. Raun15

The environmental impact of recombinant bovine somatotropin (rbST) use in dairy production Judith L. Capper,* Euridice Castañeda-Gutiérrez,*† Roger A. Cady,‡ and Dale E. Bauman* Proc Natl Acad Sci U S A. 2008 July 15; 105(28): 9668–9673

The environmental impact of dairy production: 1944 compared with 2007. Journal of Animal Science,Capper, J. L., Cady, R. A., Bauman, D. E. 2009; 87 (6): 2160 DOI: 10.2527/jas.2009-1781

Environmental impacts of genetically modified (GM) crop use 1996–2015: Impacts on pesticide use and carbon emissions
Graham Brookes & Peter Barfoot
GM Crops & Food Vol. 8 , Iss. 2,2017

Batista R, Saibo N, Lourenço T, Oliveira MM. Microarray analyses reveal that
plant mutagenesis may induce more transcriptomic changes than transgene
insertion. Proc Natl Acad Sci U S A. 2008 Mar 4;105(9):3640-5. doi:
10.1073/pnas.0707881105. PubMed PMID: 18303117; PubMed Central PMCID: PMC2265136

Baudo MM, Lyons R, Powers S, Pastori GM, Edwards KJ, Holdsworth MJ, Shewry PR. (2006). Transgenesis has less impact on the transcriptome of wheat grain than conventional breeding. Plant Biotechnol J. 2006 Jul;4(4):369-80

Single Peaked Preferences and the Median Voter Theorem

In the last entry on voting paradoxes, I mentioned that things are different if preferences are single peaked.

Let’s look at another scenario. Again, consider a set of policies A,B,C following a sequence from  (A) less to more extreme (C) - maybe tax rates or some level of spending- with (B) being the intermediate policy. Suppose voters rank policies in order of preference/utility as follows:

Voter X:  ABC
Voter Y : CBA
Voter Z : BCA

In this case, no matter what order is undertaken, B always ends up being the law that is enacted. These preferences are single peaked. Each individual has a most preferred choice along the A to C spectrum. If you move away from that choice (in the A-B-C spectrum) they prefer the other choices less.  In the previous example, voter Y did not have single peaked preferences and that is what caused the cycling or order dependent outcomes. With single peaked preferences there is a new problem. With single peaked preferences, the median point of the preference distribution will elicit the most votes. Only those laws or candidates with a centrist twist will get the majority of the votes. Only those voters with centrist views will be happy, and it makes it very difficult for candidates to be elected if they want to bring about major reforms. This phenomenon is referred to as the ‘median voter theorem.’

Both voter cycling (when preferences are not single peaked) and the median voter theorem can have negative implications for majority rule policy adoption. Voters are either governed by irrational ever changing majorities, or they are subjugated by entrenched majorities whose views are maintained by the status quo of median preferences.

References:

Lemieux, Pierre, The Public Choice Revolution. Regulation, Vol. 27, No. 3, pp. 22-29, Fall 2004. Available at SSRN: https://ssrn.com/abstract=604046

Majority Rule and Vote Cycling with Non-Single Peaked Preferences

Is majority rule the best way to represent voters preferences for a given set of policies?

Let’s look at a particular voting scenario to illustrate this. Consider a set of policies A,B,C following a sequence from  (A) less to more extreme (C) - maybe tax rates or some level of spending- with (B) being the intermediate policy. Suppose voters have the following preferences:


VOTER X: A >B >C  'single peaked '

VOTER Y: C>A>B

VOTER Z: B>C >A  'single peaked'

Both voters X and Z have single peaked preferences. As we move away from their optimal choice the strength of their preferences or utility decreases. However, voter Y does not exhibit single peaked preferences. They prefer the extreme policy C most, but their next preferred policy is in the direction of the other extreme A. They prefer the intermediate policy B least.

If the voters were voting on these issues, voter X would prefer law A over law B and law B over law C. In shorthand – A >B >C. To summarize all of the choices of the voters we see that 2/3 of the voters have preference A >B, 2/3 of the voters have preference B > C, but when voting A vs. C, 2/3 have preference C >A.

See if you follow the application of this. If we vote on policies in a pairwise fashion and have two elections and the first is made between policy B and C, then B will win (2/3 of the voters have preference B > C). If this is followed by a second election A vs. B (Because C was eliminated in the first election) then A will be the law that ultimately passes by majority rule.


Now if the order is changed, in which the first election is between A and B, A will win (because 2/3 of the voters rank A > B). Then in the second election when A goes against C, C will be the law that passes by majority rule (again because 2/3 of the voters have preference C >A).

So when voting on these policies, the process becomes arbitrary. The outcome depends on the order of the vote, so a cycling of choices ensues. According to public choice economist Gordon Tullock, any outcome can be obtained in majority voting by at least one voting method. This indicates that majorities can be irrational and dangerous unless preferences are all single peaked. 

Reference:

Lemieux, Pierre, The Public Choice Revolution. Regulation, Vol. 27, No. 3, pp. 22-29, Fall 2004. Available at SSRN: https://ssrn.com/abstract=604046

Risk, Uncertainty, Speculation and Granger Causality

What is the difference between 'risk' and 'uncertainty'?

"Uncertainty refers to outcomes that we cannot foresee, or whose probabilities that we cannot estimate. In other words, uncertainty is a way of characterizing what we don't know about the distribution of the random variables themselves...Risk can be quantified, priced,and traded. It can even be hedged with large pools of assets." - Froeb et al 2014.Managerial Economics: A problem solving approach. 3rd edition.

This distinction was first made by economist Frank Knight.

Insurance of all kinds and commodity futures markets are examples of financial products based on quantifiable risks. Those involved in these markets, often speculators, have an important role to play. Speculators and futures and options markets make it possible to allocate resources across time, essentially from periods of abundance to periods of scarcity smoothing consumption and alleviating risks.

This is described well in The Economic Way of Thinking:

"Speculators coordinate market exchanges through time...that both inform people and provide them with the opportunity to allocate their risks...Speculators accept the risk at a mutually agreed upon price that hedgers seek to avoid."

Elaine Kub, author of Mastering the Grain Markets puts it beautifully in her book:

"All life on earth depends on agriculture, how well we distribute agriculture's products-how well we trade grain-determines how Earth's population gains access to its most fundamental needs."

However, speculators and funds involved in commodities trading often come under heavy scrutiny perhaps without understanding the important role they play in actually increasing food security as Nevil Speer explains below:

“Reining in speculators seems politically expedient.  But we live in complex times.  Throwing darts becomes perilous when policy makers begin to advocate (and worse yet, actually believe) that speculators should be removed  from ag / food markets.   Such a move would dismantle futures markets.  Imagine what the world might look like a without market liquidity, price discovery and risk mitigation; not to mention the inability to establish pricing plans, attract new capital investment and stimulate innovation across the food business.   The absence of those influences, facilitated by futures markets, would ultimately lead to less food production, availability and security – NOT the other way around.  Taking speculators out of the mix would be devastating.”  Dr. Nevil Speer, No Speculators? No thanks!, Drovers Cattle Network Agsight, March 2011

So what impact have speculators had on markets? One way is to look at the impact of index funds on commodity prices and volatility. Economist Scott Irwin at the University of Illinois has looked at this in depth. Below are three examples of studies (although not a complete review of the literature) looking at these impacts based on granger causality tests and other methods:

The Impact of Index Funds in
Commodity Futures Markets:
A Systems Approach
DWIGHT R. SANDERS AND SCOTT H. IRWIN
The Journal of Alternative Investments
Summer 2011, Vol. 14, No. 1: pp. 40-49

"The system of Granger-style causality tests fails to reject the null hypothesis that that trader positions do not lead market returns. Hence, there is no evidence of a linkage between index trader positions in commodity futures markets and price levels."

Irwin, S. H. and D. R. Sanders (2010), “The Impact of Index and Swap Funds on Commodity Futures Markets: Preliminary Results”, OECD Food, Agriculture and Fisheries Working Papers, No. 27, OECD Publishing. doi: 10.1787/5kmd40wl1t5f-en

“There is no statistically significant relationship indicating that changes in index and swap fund positions have increased market volatility......at this time, the weight of evidence clearly suggests that increased index fund activity in 2006-08 did not cause a bubble in commodity futures prices.”

Index Trading and Agricultural Commodity Prices:
A Panel Granger Causality Analysis
Gunther Capelle-Blancard and Dramane Coulibaly
CEPII, WP No 2011 – 28
No 2011 – 28
December

"Our results show that, in agricultural futures markets, there is no evidence of a causality relationship from index funds to futures prices. This result holds for the period 2006-2010, but also for the sub-periods 2006-2008 and 2008-2010. These findings imply that index-based trading has not been an important driver in the substantial increase in commodities prices. Changes in commodity prices may instead reflect fundamental supply and demand factors."


References:

Explained: Knightian uncertainty
The economic crisis has revived an old philosophical idea about risk and uncertainty. But what is it, exactly?
Peter Dizikes, MIT News Office
June 2, 2010

Foeb, Mcann, Ward, and Shor. Managerial Economics: A problem solving approach. 3rd edition. 2008.

The Economic Way of Thinking. Heyne, Boettke, and Prychitko. 10th Edition. 2002.

Mastering the Grain Markets: How profits are really made. Elaine Kub.

See also: 

Fat Tails, Kurtosis, and Risk

Fat Tails, the Precautionary Principle and GMOs

Stawman Arguments Against Statements Related to GMO Safety

Previously I discussed how the World Health Organization, the American Medical Association, and the National Academy of Sciences have all issued statements regarding the safety of foods derived from genetically engineered crops.

In addition I discussed how critics have questioned these statements. One set of assertions supports the invocation of the precautionary principle.

I have written before about issues related to using the precautionary principle with respect to genetically modified vs conventional food crops.

In this post I would like to specifically discuss the assertion that  "There are no epidemiological studies investigating potential effects of GM food consumption on human health."

To those unfamiliar with modern crop science and genetics, that could sound like a very condemning statement. But that begs the question, have there been epidemiological studies investigating the potential effects of conventionally and mutagenically improved crops on human health?

Its also a true statement that there are no epidemiological studies investigating the relative safety of using the stairs vs. elevators vs. escalators vs. leaping out the top floor window with regard to human health. (although I am sure actuaries have assessed property/casualty probabilities associated with similar kinds of risks related to building design, we don't have people losing sleep over lack of publication in this area)

These last examples might seem extreme and unrelated, but they illustrate the point that for some things, conducting an expensive (and difficult) epidemiological study to assess impacts on human health makes little practical sense. 

What reasoning would make us think this is necessary for genetically modified foods? If we were discussing inclusion of traits known to impact metabolism or hormone levels or some other biological function this might make sense. But the types of crops approved for human consumption don't have traits known to behave this way. Some critics might assert that it is the unknown consequences (changes in DNA, changes in proteins, or metabolism) that we should be worried about. 

However, scientists know that these kinds of genetic disruptions are not any more proliferate with genetically engineered crops than those related to traditional and mutagenic crop improvement that have been consumed and accepted by consumers without question for hundreds (thousands) of years or more in some cases and decades in others. They are substantially equivalent in this regard.

It turns out that the statement about the absence of epidemiological studies is really irrelevant when it comes to assessing the risks associated with genetically engineered food consumption. Arguments using epidemiological studies to form a psychological baseline or frame of reference are akin to strawman statements that could raise unnecessary doubts and fears about a technology that actually exhibits characteristics beneficial to human health and the environment.

References:

No scientific consensus on GMO safety. Environmental Sciences Europe. 2015 27:4

Batista R, Saibo N, Lourenço T, Oliveira MM. Microarray analyses reveal that
plant mutagenesis may induce more transcriptomic changes than transgene
insertion. Proc Natl Acad Sci U S A. 2008 Mar 4;105(9):3640-5. doi:
10.1073/pnas.0707881105. PubMed PMID: 18303117; PubMed Central PMCID: PMC2265136

Baudo MM, Lyons R, Powers S, Pastori GM, Edwards KJ, Holdsworth MJ, Shewry PR. (2006). Transgenesis has less impact on the transcriptome of wheat grain than conventional breeding. Plant Biotechnol J. 2006 Jul;4(4):369-80

First citation:

Defining Consensus Regarding the Safety of Genetically Modified Foods

The World Health Organization, the American Medical Association, and the National Academy of Sciences have all issued statements regarding the safety of foods derived from genetically engineered crops. However, in a recent letter critical of the documentary film Food Evolution, the following paper is cited:

No scientific consensus on GMO safety. Environmental Sciences Europe. 2015 27:4
Link

This was the first time I had seen this paper so I spent some time going through it to see what kinds of arguments were being made. Below are a few excerpts and some discussion.

"the scarcity and contradictory nature of the scientific evidence published to date prevents conclusive claims of safety, or of lack of safety, of GMOs. Claims of consensus on the safety of GMOs are not supported by an objective analysis of the refereed literature."

"The health, environment, and agriculture authorities of most nations recognize publicly that no blanket statement about the safety of all GMOs is possible and that they must be assessed on a 'case-by-case' basis."

"There are no epidemiological studies investigating potential effects of GM food consumption on human health"

"an expert panel of the Royal Society of Canada issued a report that was highly critical of the regulatory system for GM foods and crops in that country. The report declared that it is 'scientifically unjustifiable' to presume that GM foods are safe without rigorous scientific testing and that the 'default prediction' for every GM food should be that the introduction of a new gene will cause 'unanticipated changes' in the expression of other genes, the pattern of proteins produced, and/or metabolic activities."

"We support the application of the Precautionary Principle with regard to the release and transboundary movement of GM crops and foods."

 I have not had a chance to check every single reference and citation made. However the general framework sketched out in the paper I am getting is this:

• there is no absolute or conclusive evidence that genetically engineered foods are safe or unsafe
• the risks are associated with unintended effects related to gene insertions (i.e. genetic disruptions)
•  invocation of the precautionary principle is used to obviate the statements often cited by the World Health Organization, the American Medical Association, and the National Academy of Sciences

This leads me to ask, can we make a blanket statement about the safety of all conventionally modified or organic foods that utilize plant breeding and mutagenesis? Have there been epidemiological studies investigating the effects of these methods on human health?

Suddenly this thinking brings up a question I have addressed before: why would we invoke the precautionary principle in the case of  food from genetically engineered crops and not for conventionally and mutagenically improved crops? 

From the literature:

“We found that the improvement of a plant variety through the acquisition of a new desired trait, using either mutagenesis or transgenesis, may cause stress and thus lead to an altered expression of untargeted genes. In all of the cases studied, the observed alteration was more extensive in mutagenized than in transgenic plants” - (Batista, et al; 2008)

With greater disruptions, critics might favor increased regulatory scrutiny. However, we do not have a framework in place for mutagenically improved crop varieties that have been safely used for decades and approved by the organic food industry and accepted by consumers, nor do we have anything like this for conventionally bred crops. If an argument for the precautionary principle holds for genetically engineered crops on this basis, then it should also hold for all types of crop improvement.

Therefore it seems tenuous to make a scientific risk based justification for special treatment of genetically engineered crops without further evidence. When many refer to a consensus on the safety of genetically engineered foods, this is what I have in mind.

Policies related to genetically engineered foods leveraging the precautionary principle could lead to increased risk of doing more harm than good to human health and the environment if policies prevent or delay adoption of traits that could decrease use of toxic pesticides, or reduce carbon emissions and improve soil conservation as some biotech traits have been shown to do in the literature.

See also:

Fat Tails, The Precautionary Principle, and GMOs
Comments on Rules for Gene Editing Technology
Organic Activists Realize Hypocrisy in Opposition to Gene Editing Technology

References:

Batista R, Saibo N, Lourenço T, Oliveira MM. Microarray analyses reveal that
plant mutagenesis may induce more transcriptomic changes than transgene
insertion. Proc Natl Acad Sci U S A. 2008 Mar 4;105(9):3640-5. doi:
10.1073/pnas.0707881105. PubMed PMID: 18303117; PubMed Central PMCID: PMC2265136

Baudo MM, Lyons R, Powers S, Pastori GM, Edwards KJ, Holdsworth MJ, Shewry PR. (2006). Transgenesis has less impact on the transcriptome of wheat grain than conventional breeding. Plant Biotechnol J. 2006 Jul;4(4):369-80

Are Soda Taxes Effective

Over at RealClearAgriculture I have been blogging about food subsidies and soda taxes.

Research from the American Journal of Clinical Nutrition finds no link to obesity and soft drink consumption.

"We showed no association between sugar-sweetened
beverage consumption, juice consumption, and adolescent weight
gain over a 5-y period. A direct association between diet beverages
and weight gain appeared to be explained by dieting practices.
Adolescents who consumed little or no white milk gained significantly
more weight than their peers who consumed white milk. Future
research that examines beverage habits and weight among adolescents
should address portion sizes, adolescent maturation, and dieting behaviors."

This corroborates previous findings from the journal Nutrition:

"Our analysis shows no evidence for an association between SSB consumption at age 5 or 7 y and fat mass at age 9 y in this cohort of British children"

A recent blog post (link) gets close to accurately reporting the issue of high fructose corn syrup- a sweetener chemically identical to table sugar found in soft drinks:

"Fructose and high-fructose corn syrup aren't the same. It appears that the writer, Lois Rogers, conflated the two and jumped to all kinds of incorrect conclusions. For example, that the research had anything at all to do with "the obesity epidemic." It didn't."

"The environmental site Grist tends to see everything through an ideological lens, and so is always on the hunt for evidence that high-fructose corn syrup is somehow more harmful than common sugar"

But then the article starts to get off track in stating:

"It is cheap (high fructose corn syrup) in large part because of farm subsidies. As a result, it is ubiquitous and is making a lot of people fat, diabetic, and prone to heart disease."

Research taking the claim of a connection between obesity and farm policy in a more direct fashion can be found here( from UC Davis).

"'The culprit here is not corn subsidies; rather,it is sugar policy that has restricted imports, driven up the U.S. price of sugar, and encouraged the replacement of sugar with alternative caloric sweeteners...Given that consumers generally show limited responses to retail food price changes, eliminating the corn subsidy would reduce corn-based food consumption by at most 0.2 percent.""

Similarly, this weak response of consumers to food prices undermines policies that advocate taxing soft drinks to reduce consumption and obesity. Research ( from the Mercatus Center at George Mason University) indicates that the taxes required to have any real affect on obesity would be in the 1200 percent range, and even if taxes eliminated ( in this case soda) consumption, the impact on obesity would be very small. The study concludes that "the sensitivity of individuals to changes in relative food prices is not sufficient to make “fat taxes” a viable tool to lower obesity."

These campaigns are nothing more than emotional appeals designed to solicit support for new taxes and regulations that ultimately undermine the agriculture industry and family farms.

References:

Media Gets Stuck in High-Fructose Corn Syrup
Dan MItchell
Daily Bread, The Business of Food Blog
The Big Money by Slate

Am J Clin Nutr doi: 10.3945/ajcn.2009.27573
Adolescent beverage habits and changes in weight over time:
findings from Project EAT1–3
Michelle S Vanselow, Mark A Pereira, Dianne Neumark-Sztainer, and Susan K Raatz

Nutrition July-August 2007, Volume 23, Issues 7-8, Pages 557-563
"Is sugar-sweetened beverage consumption associated with increased fatness in children?"

Taxing Sins: Are Excise Taxes Efficient
The Mercatus Center
George Mason University

Farm Subsidies and Obesity in the United States
Julian M. Alston, Daniel A. Sumner, and Stephen A. Vosti
Agricultural and Resource Economics Update
University of California
V. 11 no. • Nov/Dec 007