In 1983, the first scientific report on the development of genetically engineered (GE or food biotechnology, also inaccurately referred to as GMOs) plant cells was published (1). Since then, agricultural biotechnology farming has dramatically increased. The 2013 International Service for the Acquisition of Agri-Biotech Applications report found that more 4 billion people live in countries that plant GE crops. Moreover, the United States Department of Agriculture reported that in 2012, 88% of corn, 94% of cotton, and 93% of soybean harvests originated from GE plantings. These data indicate the pervasive use and impact of GE crops in the domestic and international food supply. However, even with the widespread adoption of GE practices, many have criticized the development and use of GE crops, generating fear and confusion among consumers.
Hundreds of studies have been conducted to assess the impact of GE crops. A recent study, A Meta-Analysis of the Impact of Genetically Modified Crops, aimed to empirically evaluate the agronomic, economic, and environmental impact of GE crops (2). Published in the journal PLoS One, the article by Klümper and Qaim has garnered much attention due to their findings. So what are the overall results of the study? Was the research conducted with scientifically sound methods and analyses? With the International Food Information Council (IFIC) Study Evaluation Checklist, we are able to systematically evaluate the hypothesis, design, methods, and analyses
to critically assess the results and conclusions from the study.
| Q1. Do the title and abstract reflect the study? | |
| Yes | No. View Results Skeptically |
| A1. Yes. The title indicated the purpose of the study, and the abstract succinctly details the background, objectives, methods, results, limitations, and conclusions. | |
| Q2. Is the study useful, novel, and/or relevant to humans? | |
| Yes | No. View Results Skeptically |
| A2. Yes. The study evaluated the impact of genetically engineered (GE) crops on yield, pesticide quantity, pesticide cost, total production cost, and farmer profit These outcomes are highly relevant since GE seedlings are widely used in farming practices. Moreover, the findings are extremely novel as this is one of most comprehensive research-based study to asses the impact of GE crops on various agronomic, economic, and environmental outcomes. | |
| Q3. Is the hypothesis clearly stated? | |
| Yes | No. View Results Skeptically |
| A3. No. The paper never specifically outlined a specific hypothesis. However, since the study is a meta-analysis (i.e., a type of analysis that evaluates and draws conclusions from previous findings), this type of research is not usually hypothesis-driven. | |
| Q4. Was the study methodology described in detail? | |
| Yes | No. Do the authors cite a paper for the methods? |
| A4. Yes. The study methodology was carefully described and referenced. Moreover, the authors discussed limitations (i.e., not all original reports used for the study included samples sizes and measures of variance) in their analyses and detailed possible explanations for the potential limitations. | |
| Q5. Are the methods valid, accurate and reliable? | |
| Yes | No. View Results Skeptically |
| A5. Yes. Klümper and Qaim included studies from both peer-reviewed publications as well as grey literature (i.e., findings that that are not peer-reviewed that can include conference papers, working papers, and institutional reports). Their rationale for using these types of publications was to avoid publication bias, since most peer-reviewed publications tend to only publish robust findings. While this is an obvious critique, the additional methods used by the authors were rigorously described and properly controlled. For example, some of the studies included in the analyses did not report sample sizes. To control for this, the authors limited the overall value and impact of these studies in their analyses. | |
| Q6. Does the analysis of the results make sense? | |
| Yes | No. View Results Skeptically |
| A6. Yes. The majority of the authors’ analysis used meta-regression analysis. Similar to regression analysis, which predicts outcomes based on set variables, meta-regression predicts outcomes based on effect sizes, which allows for the comparison of data among multiple studies. Using this method, the authors found that GE technology increased crop yields by 21%,and reduced pesticide quantity and cost by 37% and 39%, respectively. Additionally, the authors found that GE crops increased farmer profits by nearly 69%. Furthermore, the authors were able to further stratify and analyze the data based on specific variables such as country status, GE technology, source of funding, type of publication, etc. Examining the difference between technologies that create insect resistant (IR) or herbicide tolerant (HT) crops revealed that the type of GE technology can impact outcomes. The authors found that only IR crops caused a significant reduction in pesticide quantity. These findings were expected since the IR and HT crop technologies are drastically different. IR crops innately protect against certain pests while HT crops are not protected against any pests, indicating that IR crops should have less pesticide quantity than HT crops. Including these analyses served as a positive control for their analyses and further bolster confidence in the authors’ findings. | |
| Q7. Are the conclusions supported by the data? | |
| Yes | No. View Results Skeptically |
| A7. Yes. The authors provided detailed methods regarding their analyses to generate valid results. As such, the authors’ conclusion that the “average agronomic and economic benefits of GE crops are large and significant” is supported by the data. Moreover, the authors found that the crop yield and farmer profit gains are associated with the development status of a country. These important findings add to the overall impact of the study, indicating that GE crops may be more beneficial in developing countries. | |
| Q8. Are there conflicts of interest? (personal, academic, financial, conflicts of commitment) | |
| Yes. Compare findings to the totality of evidence. | No |
| A8. No. The study was exclusively funded from public sources, including the German Federal Ministry of Economic Cooperation and Development (BMZ) an the European Union’s Seventh Framework Programme. | |
| Q9. Does the study fit into the totality of evidence? | |
| Examine individual study findings versus the totality of evidence on the topic. | |
| A9. Yes. While there are only a few previously published studies that investigate the impact of GE crops in a systematic manner, the consensus so far is that GE crops enhance economic, agronomic, and environmental indicators (3,4) . Even though this type of research is still in its infancy, the publication by Klümper and Qaim is an excellent study that assessed the impact of GE crops on various outcomes. |
How did the study by rate after using the IFIC Checklist? The article passed nearly all of the IFIC guidelines for assessing a scientific study. While the paper reported detailed findings on the impact of GE crops on crop yield, pesticide quantity and cost, and farmer profits, the authors concluded their study by stating that their findings “may help to gradually increase public trust in this promising technology”. This last compelling point is shared among other scientific experts who are working to dissipate the confusion and fears associated with GE crops.
At a recent US House of Representatives Committee on Agriculture Hearing, a panel of scientists testified on The Societal Benefits of Agriculture Biotechnology. The panelists included Dr. David Just, a professor at Cornell University, Dr. Calestous Juma, a professor at Harvard University, and Dr. Olga Bolden-Titter, an assistant professor at Tuskegee University. The panel concluded the main societal benefits of food biotechnology were:
- Increased agricultural production
- Reduced loss due to pests, drought, and disease
- Increased environmental sustainability
Furthermore, the panelists described that GE crops enhanced health and nutrition. Dr. Juma and Dr. Just discussed how GE crops, such as golden bananas containing vitamin A, could help reduce risk of vitamin A deficiency in Uganda and the Philippines. Dr. Olga Bolden-Tiller detailed how a GE sweet potato, which has 500% more protein content than a conventional sweet potato, enhanced the diets of children in developing countries. In sum, the study by Klümper and Qaim as well as the U.S. House of Representatives Committee on Agriculture panel independently determined that the societal benefits of GE crops are quite vast. Ranging from increased production and profits, reduced crop loss and pesticide use, and improved nutritional content, GE crops will play a valuable role in future food production endeavors.
This analysis was written by Megan Meyer, Microbiology and Immunology Doctoral Student, University of North Carolina at Chapel Hill. If you liked this in-depth study analysis, you might like: Organic vs. Conventional Crops: Analyzing a Meta-Analysis.
References
1. Fraley, R.T. et al. Expression of bacterial genes in plant cells. Proc Natl Acad Sci U S A 80, 4803-4807 (1983).
2. Klumper, W. & Qaim, M. A meta-analysis of the impacts of genetically modified crops. PLoS One 9, e111629 (2014).
3. Carpenter, J.E. Peer-reviewed surveys indicate positive impact of commercialized GM crops. Nature biotechnology 28, 319-321 (2010).
4. Brookes, G. & Barfoot, P. The income and production effects of biotech crops globally 1996-2010. GM crops & food 3, 265-272 (2012).
