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The Biostatistics work package performs statistical analyses of the results from the rodent feeding studies, reports on the results, and provides recommendations on the statistical methodology for long-term feeding trials.


The statistical power attainable for the primary parameters of toxicological interest when using sample sizes as specified in the standard OECD protocols is evaluated in a prospective power analysis.


The purpose of the statistical analysis is to derive point and interval estimates of the difference in parameters between the NK603-fed groups and the control group. These estimates are compared to a null hypothesis of equality (classical approach, differences tests) and to null hypotheses specifying a difference equal to external equivalence limits (G-TwYST approach, equivalence tests). Equivalence limits indicate minimum differences of potential toxicological relevance. For setting the equivalence limits use is made of data from non-GM groups in the feeding studies of the GRACE project.

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G-TwYST Interim Report available

15 February 2017


The G-TwSYT team completed a publicly available Interim report with information about the progress that has been made in the first 1.5 years of the project. The report can be downloaded here.

Value and pitfalls of stakeholderconsultation

17 January 2017


In 2013 the Dutch Commission on Genetic Modification (COGEM) published a topic report on alarming studies on the safety of GMOs. COGEM pointed out that while repetition of ‘alarming studies’ is sometimes the only way to reject or confirm the results, stakeholder participation during investigation may increase its social robustness.

In a letter sent to the Secretary of State of Infrastucture and Environment on January 11, 2017 COGEM adds some reflections on the value and possible pitfalls of stakeholder participation based on experiences in and results of the GRACE project.

The COGEM letter states that the involvement of stakeholders in this project has been meticulous and transparent and has finally contributed to the validity of the results also from a broader social perspective. However, COGEM also noticed that some stakeholders were too fixated on their own arguments and vision, that reflection and interaction became difficult. According to COGEM this situation significantly hampered the achievement of broadly supported conclusions. On the basis of this experience COGEM also proposed some guidelines for improving such processes.


Read the full letter >

Scientific quality criteria (2)

28 November 2016


So far, we have received comments on the proposed scientific quality criteria from the Federal Office of Consumer Protection and Food Safety, Germany (BVL) on October 5th, 2016. The comments can be downloaded here.


The G-TwYST research team responded to the BVL comments on November 28th, 2016. The response can be downloaded here.