DIN Standards Committee Water Practice
DIN ISO 11352
Water quality - Estimation of measurement uncertainty based on validation and quality control data (ISO 11352:2012)
Wasserbeschaffenheit - Abschätzung der Messunsicherheit beruhend auf Validierungs- und Kontrolldaten (ISO 11352:2012)
Overview
The basic principles of the estimation of measurement uncertainty are described in ISO/IEC Guide 98-3, Guide to the expression of uncertainty in measurement (GUM). There are several ways of estimating measurement uncertainty depending on the purpose of the estimation and the available data; a new EUROLAB report gives an overview of the main approaches. This standard describes procedures to enable laboratories to estimate the measurement uncertainty of their results, using an approach based on quality control results and validation data. It is structured in a way that is applicable to analysts that do not have a thorough understanding of metrology and statistics. The Dutch standard NEN 7779 "Environment - Measurement uncertainty" and Nordtest TR 537 have been used as a basis for developing this standard. The approach taken is "top-down", contrary to the mainly "bottom-up" strategy adopted in ISO/IEC Guide 98-3. It is statistically acceptable to combine a precision estimate and the uncertainty associated with the bias into one uncertainty measure. The sources of data for this approach are method validation and analytical quality control. The experimental approach described in this standard enables a greater coverage of the sources of variation observed during routine use of the analytical method. The International Standard ISO 11352:2012 has been prepared by Technical Committee ISO/TC 147 "Water quality" the secretariat of which is held by DIN (Germany). Regarding the German collaboration, the responsible committee is NA 152-01-12-02 AK "Messunsicherheit" ("Measurement uncertainty") at the Water Practice Standards Committee (NAW).
