15121 IUPAC Gold Book - uncertainty factor 10.1351/goldbook.15121 15121 current initialism: UF synonyms: application factor (AF), assessment factor, modifying factor (MF), safety factor 1 In assay methodology, confidence interval or fiducial limit used to assess the probable precision of an estimate. In toxicology, value used in extrapolation from experimental animals to humans (assuming that humans may be more sensitive) or from selected individuals to the general population.Example: A value applied to the no-observed-effect-level (NOEL) or no-observed-adverse-effect-level (NOAEL) to derive an acceptable daily intake (ADI) or tolerable daily intake (TDI).Note: The NOEL or NOAEL is divided by the value to calculate the ADI or TDI. population https://goldbook.iupac.org/terms/view/14932 PAC, 2009, 81, 829. 'Glossary of terms used in ecotoxicology (IUPAC Recommendations 2009)' on page 961 (https://doi.org/10.1351/PAC-REC-08-07-09) https://goldbook.iupac.org/terms/view/15121/html https://goldbook.iupac.org/terms/view/15121/json https://goldbook.iupac.org/terms/view/15121/plain Citation: 'uncertainty factor' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.15121 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-06-29T14:53:56+00:00