People on the Land: Correlation, Causation, and GMOs

Some folks want to shut down debate about genetically modified organisms (GMOs) with an absolutist’s appeal to statistical logic. But with so much murky information, maybe correlation is the best we can do for now.

Sometimes, phrases get tossed around to the point where they become meaningless. So it goes with “correlation does not imply causation.”

In fact, here’s a correlation: The phrase, badly used outside of the world of statistics, raises my hackles. It is often intended to shut down discussion, and, in context, might be taken as snarky.

A recent discussion of genetically modified organisms (GMO) in foods with a long-time friend triggered this column when he used the phrase. We were talking about a recent article in Slate by William Saleton that lists errors reported by organizations opposing GMOs. First, I appreciate the chance to read about the alleged errors because I am nowhere near an expert in this area. Second, I appreciate the suggestion that we need more critical thinking about the topic. But two things bother me:

1) The article’s one-sidedness is problematic. I cannot argue with the author’s conclusions about nonprofits’ fabrications and misleading arguments without a lot of fact checking. I won’t deny the possibility outright. After all, these organizations have donors to keep happy, and yes, let’s be open-minded, they can be just plain wrong or unscrupulous.


But Saleton does not examine the possibility of misleading statements from the GMO industry, which, after all is profit-driven, beholden to investors and stockholders. The attacks on GMO opponents remind me of the industry-led barrage launched against Rachel Carson when Silent Spring was published more than half a century ago. Her groundbreaking work turned out to be valid and influential.

2) Worse still is the misunderstanding of science with the implied claim that GMOs are safe. Some research says they are. Other research still raises questions. The big question is whether we have had enough time to understand whether GMOs are safe, especially in the context of overall environmental conditions and interactions with individuals’ health. We may be safe in the short run, but what about the long run?

Food science is dynamic, and research on cholesterol and diabetes provides evidence of how knowledge evolves. At one time, eggs and butter were thought to raise cholesterol levels. Now new research suggests they’re not so bad. Margarine was thought to be good. Now it’s not, because of the nature of corn oil and how it is digested. Corn syrup was touted as a perfect substitute for sugar. Now, we have big questions about its relationship to Type II diabetes. We are constantly learning and relearning over time about our bodies and the food we eat, and we are only at the beginning of GMO use.

Humans have been making genetic modifications to food products for a long time. We have been increased farm productivity and improved quality (although that is a matter of aesthetics). But only recently have we gained the ability to insert new material, such as a pesticide or herbicide, into a plant’s basic code for life.

Let me state here that I am not against GMOs. But I have a lot of questions not only about them, but how they fit into our whole food processing and distribution system. How we create, harvest, and process our food adds variability to the GMO equation, making it difficult to parse out impacts. If studies suggest a certain GMO is safe for consumers, the qualification “for now” seems to me an important ethical requirement. Science never proves anything, but it does modify a constantly changing body of knowledge.

Causation does not equal correlation, as they say.
Correlation does not imply causation, as they say. While this example may be absurd, the science around genetically modified organisms is far less certain, the author argues.

From a public policy perspective, science seldom is a deciding factor in decisions. After 40-plus years of viewing and analyzing policy debates, I have learned ad nauseam that at the simplest level, ideology and power—political and financial—shape our perceptions and our policy debates.

Analyzing the science of GMOs is far too complex for us mere mortals, and the atmosphere is charged with the sparks of axes being ground by politicians seeking votes; nonprofits seeking wider audiences and funding sources; and for-profit corporations that are more beholden to the bottom line than conscience.

Corporate secrecy—including resistance to labeling products—fosters distrust and imposes severe limits on freedom of information necessary for scientific discourse and policy discussions. Rachel Carson stumbled into the power of this secrecy with Silent Spring, and, although corporations have responded to some demands for more environmental responsibility, the profit motive and secrecy about GMOs cultivate consumer suspicion, whether based on science, corporate motives, individuals’ perceptions, or fear of the unknown.

GMOs raise questions not only because of the economics, but from the perspectives of health, the environment, and overall social welfare. The impacts of GMOs—real and potential—resound across the whole environment. We cannot dismiss these impacts lightly because what is happening is so complex. Simple cause-effect arguments are problematic because the dynamics of environmental systems allow for numerous interactions not yet well understood.

When intricate public policy issues get personal, such as with GMO foods, the chance of separating emotion from discussion is slim, especially if politicians, companies, and organizations manipulate perceptions instead of offering paths to reasonable debate. Our discussions about GMOs need to move beyond basic emotional appeals. Perception-shaping is a crafty approach that suggests how we can be misled and manipulated, even by people and groups we might consider to be on our side.

Concerned citizens want good information, but they may not know whom to trust. So, they often resort to correlation. When facts are gray, malleable, and changeable, correlation—coupled with careful, systematic observation and openness to filtering knowledge from conflicting sources—may be all we have. Reasoned correlation is integral not only for good scientific research. It is important to developing opinions about policymaking questions and discussions.

Until we can do better in policy discussions, “correlation does not imply causation” should not be a quip that in essence says, “Sit down and shut up.”

Reasoned correlation is certainly better than acting based on perceptions. In other words, those who consider correlations are doing the best we can with what we’ve got.

Timothy Collins is assistant director for research, policy, outreach, and sustainability at the Illinois Institute for Rural Affairs at Western Illinois University in Macomb. Opinions expressed here are his and his alone. He is the proprietor of Then and Now Media and author of Selling the State: Economic Development Policy in Kentucky.

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