Title: confidence level
Long Title: IUPAC Gold Book - confidence level
DOI: 10.1351/goldbook.C01246
Status: current

Definition
The probability of covering the expected value of an estimated parameter with an interval estimated for the parameter (symbol \(1 - \alpha\)). The confidence level can be expressed as a number between 0 and 1, or in percent. The complementary quantity is known as the significance level.

Note
In some cases the confidence level is dictated by the needs of the situation. In all other instances, use of \(1 - \alpha = 0.95\) is recommended.

Related Terms
- expected value: https://goldbook.iupac.org//terms/view/M03796
- percent: https://goldbook.iupac.org//terms/view/P04483
- probability: https://goldbook.iupac.org//terms/view/P04855

Source
- PAC, 1994, 66, 595. 'Nomenclature for the presentation of results of chemical analysis (IUPAC Recommendations 1994)' on page 599 (https://doi.org/10.1351/pac199466030595)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/C01246/html
- json: https://goldbook.iupac.org/terms/view/C01246/json
- xml: https://goldbook.iupac.org/terms/view/C01246/xml

Citation: Citation: 'confidence level' 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.C01246
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Accessed: 2026-07-24T21:25:15+00:00