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The principles and methods behind EFSA's Guidance on Uncertainty Analysis in Scientific Assessment

Benford, Diane; Halldorsson, Thorhallur; Jeger, Michael John; Knutsen, Helle Katrine; More, Simon; Naegeli, Hanspeter; Noteborn, Hubert; Ockleford, Colin; Ricci, Antonia; Rychen, Guido; Schlatter, Josef R; Silano, Vittorio; Solecki, Roland; Turck, Dominique; Younes, Maged; Craig, Peter; Hart, Andrew; Von Goetz, Natalie; Koutsoumanis, Kostas; Mortensen, Alicja; Ossendorp, Bernadette; Germini, Andrea; Martino, Laura; Merten, Caroline; Mosbach‐Schulz, Olaf; Smith, Anthony; Hardy, Anthony

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Diane Benford

Thorhallur Halldorsson

Michael John Jeger

Helle Katrine Knutsen

Simon More

Hanspeter Naegeli

Hubert Noteborn

Colin Ockleford

Antonia Ricci

Guido Rychen

Josef R Schlatter

Vittorio Silano

Roland Solecki

Dominique Turck

Maged Younes

Andrew Hart

Natalie Von Goetz

Kostas Koutsoumanis

Alicja Mortensen

Bernadette Ossendorp

Andrea Germini

Laura Martino

Caroline Merten

Olaf Mosbach‐Schulz

Anthony Smith

Anthony Hardy


To meet the general requirement for transparency in EFSA's work, all its scientific assessments must consider uncertainty. Assessments must say clearly and unambiguously what sources of uncertainty have been identified and what is their impact on the assessment conclusion. This applies to all EFSA's areas, all types of scientific assessment and all types of uncertainty affecting assessment. This current Opinion describes the principles and methods supporting a concise Guidance Document on Uncertainty in EFSA's Scientific Assessment, published separately. These documents do not prescribe specific methods for uncertainty analysis but rather provide a flexible framework within which different methods may be selected, according to the needs of each assessment. Assessors should systematically identify sources of uncertainty, checking each part of their assessment to minimise the risk of overlooking important uncertainties. Uncertainty may be expressed qualitatively or quantitatively. It is neither necessary nor possible to quantify separately every source of uncertainty affecting an assessment. However, assessors should express in quantitative terms the combined effect of as many as possible of identified sources of uncertainty. The guidance describes practical approaches. Uncertainty analysis should be conducted in a flexible, iterative manner, starting at a level appropriate to the assessment and refining the analysis as far as is needed or possible within the time available. The methods and results of the uncertainty analysis should be reported fully and transparently. Every EFSA Panel and Unit applied the draft Guidance to at least one assessment in their work area during a trial period of one year. Experience gained in this period resulted in improved guidance. The Scientific Committee considers that uncertainty analysis will be unconditional for EFSA Panels and staff and must be embedded into scientific assessment in all areas of EFSA's work.


Benford, D., Halldorsson, T., Jeger, M. J., Knutsen, H. K., More, S., Naegeli, H., …Hardy, A. (2018). The principles and methods behind EFSA's Guidance on Uncertainty Analysis in Scientific Assessment. EFSA Journal, 16(1), Article e05122.

Journal Article Type Article
Acceptance Date Nov 15, 2017
Online Publication Date Jan 24, 2018
Publication Date Jan 24, 2018
Deposit Date Jan 25, 2018
Publicly Available Date Jan 30, 2018
Journal EFSA Journal
Print ISSN 1831-4732
Publisher Wiley Open Access
Peer Reviewed Peer Reviewed
Volume 16
Issue 1
Article Number e05122


Published Journal Article (15.5 Mb)

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Copyright Statement
© 2018 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority. This is an open access article under the terms of the Creative Commons Attribution-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited and no modifications or adaptations are made.

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