ISO 5667-20:2008 Water quality - Sampling - Part 20: Guidance on the use of sampling data for decision making - Compliance with thresholds and classification systems
International Organization for Standardization (ISO)
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ISO 5667-20:2008
Scope
This part of ISO 5667 establishes principles, basic requirements, and illustrative methods for dealing with the
use of sample data for decision making based on the assessment of the confidence that water quality:
a) meets targets and complies with thresholds;
b) has changed; and/or
c) lies in a particular grade in a classification system.
This part of ISO 5667 also specifies methods for preliminary examination of the sensitivity of decisions to error
and uncertainty, although it does not cover the full range of statistical techniques.
This part of ISO 5667 provides general advice on decision making related to constraint formulation for
expression of thresholds and targets and the form and scale of sampling programmes.
NOTE 1 In the water industry, "standard" is commonly used to indicate the value or limit of a parameter of interest
However, in this part of ISO 5667, the term "threshold" is used to avoid confusion with published national, regional, and
International Standards.
NOTE 2 This document is framed in terms of sampling and measurement of chemical concentrations, in particular
those subject to strong day-to-day temporal variations. The principles apply, however, to any item estimated by sampling
which is subject to random error, including microbiological and biological data, and data subject to strong spatial variations.
ISO 5667-20:2008 history
2008ISO 5667-20:2008 Water quality - Sampling - Part 20: Guidance on the use of sampling data for decision making - Compliance with thresholds and classification systems