View from the fence

Social, environmental and economic issues surrounding GM foods, and the latest news

What is evidence?

The internet is flooded with information about GM, but as I walk the tightrope of the middle ground I need to decide what actually constitutes reliable evidence. There are lots of accusations that sources are unreliable because they are from people who are book-burning luddites, or in the pocket of evil corporations.  It’s a convenient way to dismiss evidence which doesn’t suit you, but how do you know when this ‘evidence’ should be dismissed?

I want the debate to be about evidence, not about insulting other people’s motives, but at the same time I need to decide which evidence is reliable, and the motives of people presenting it are part of that decision. I often wish that I could do all the experiments myself, but sadly I have to rely on what I read.

Here are my thoughts – I’d be interested to hear from people who agree/disagree.

What do I take as evidence?

Peer-reviewed journals are a major source of information for me.

For anyone who isn’t familiar with the peer review system, basically scientists write papers about their findings, including the background information, the way they did their experiments, what their results were, and what they believe this means. This is then reviewed by at least two (usually anonymous) independent scientists before the paper is accepted by a journal. This can be primary research, by the scientists who did the experiments, or reviews, in which the authors have synthesised other research.

In many ways this is evidence as good as it gets – someone has actually done an experiment to find out what is going on. There are reasons why we shouldn’t get too complacent; just because something is peer-reviewed it isn’t necessarily right. I’m interested in ways of improving academic publishing, something I’ve been giving even more thought to since the retraction of Seralini’s paper, but the system we have does give me access to some excellent science.

One fuzzy area for me is peer-reviewed papers where the authors are from companies rather than research organisations. There is some excellent science done by researchers in private companies, and I am not accusing them of fabricating results. But have they avoided doing some relevant experiments because it might not reflect well on their products? Or done experiments which, for example, showed their products to be ineffective and then chosen not to publish them? For my 30th birthday I am having a ‘saving the world’ party, where I get together with friends and family to talk about saving the world. This is a topic I want to discuss, and in advance I would very much appreciate comments under this post.

The pharmaceutical industry is an interesting illustration. Putting profit above welfare has led to some dubious ethical practices, but ultimately I live a life entirely unaffected by epilepsy because I take tablets they developed. Currently an ‘All Trials’ campaign is pressurising the industry to register all clinical trials – to avoid companies publishing the results which suit them and hiding the ones which don’t show treatments to be effective.

In addition to peer-reviewed research I am interested to hear the opinions of respected scientists, and anyone involved in the social and economic arguments associated with GM crops. These experts are more widely read than I am and often their opinion pieces put research in its wider context. I am, however, here to make up my own mind.

What do I not take as evidence?

Corporate websites, e.g. Monsanto
A good source of answers to questions about what products are available, for example, but I don’t expect them to present information which conflicts with their profits. It isn’t somewhere I’ll go to investigate the environmental impacts of their products.

Anti-GM campaign groups, e.g. GM Watch
There are plenty of organisations who have decided they are inherently against genetic modification, and therefore will only present evidence which supports their point of view. Governments are often accused of ‘policy based evidence’ rather than ‘evidence based policy’ – deciding on their policy then collecting evidence which supports it, rather than making policy decisions based on all the evidence. I believe this is exactly the situation with many organisations campaigning against GM, and at the very least it causes them to cherry pick evidence, ignoring or disputing any which is inconvenient. I might use them to alert me to new research published in a journal, but I will go back to the original source for an un-biased assessment. There are groups, such as the Institute for Responsible Technology, which when I first come across them I think ‘yes, responsible technology that’s what I’m after’ then on closer inspection they are simply anti-GM campaigns with a neutral name.

What traps do I want to avoid?

Bias in the evidence I choose
There is more evidence out there than I can possibly read, even in peer-reviewed literature. There are plenty of people who have dealt with this by only reading evidence which fits their point of view. This is the trap I feel I must work hardest to avoid, even though my view remains on the fence.

False balance
This is a stereotypical BBC problem – when a GM story hits the news they often look for an interviewee who is pro-GM and one who is anti-GM. It doesn’t matter that the actual debate is far more complex, and that there isn’t a 50:50 split of views – their format is a one on one. It’s balance, but not a fair representation of the situation.

It’s yes v no
Evidence which initially appears to be conflicting on closer inspection may not be. Just because one paper reports altered yield in a GM crop, for example, that doesn’t mean that other GM crops don’t show very different stories.

A million people can’t be wrong
Thousands of anti-GM tweets by well-meaning people often feels overwhelming, but it isn’t evidence in itself. It’s a very human urge to go with the masses, but I like to read the links before I make decisions. An example is the 285,000 signatures on the 38 Degrees petition to ban neonocotinoid pesticides. How many people had actually looked at the science behind the ban? The picture was far more complex than was widely presented. I want to be the person who looks at the science.

Author: Rebecca Nesbit

I am author of a popular science book 'Is that Fish in your Tomato?' exploring the fact and fiction of GM crops. In my work and leisure so far, I have trained bees to detect explosives, used a radar to study butterflies for my PhD, written a novel, taken the train from London to China, organised Biology Week, sold science jewellery on Etsy, and traveled to four continents with Nobel Laureates. Best off all, I've made lots of friends whose support I very much appreciate. Thank you! Please visit my website:

Comments are closed.