Information leaflets

Information leaflets

Information leaflets

You talk, we understand – The way out of the tower of Babel

Contents

Babel 150This leaflet, prepared by the Eurachem Education and Training Working Group, explains the importance of having a common language when discussing measurements. It highlights some terms which are commonly confused or misunderstood, references the International Vocabulary of Metrology ("the VIM"), and introduces the Eurachem Guide on Terminology in Analytical Measurement.

This second edition updates the Information Leaflet to align with the second edition of the Eurachem Guide "Terminology in Analytical Measurement", published in 2023.

 

Availability

This second edition of the information leaflet is currently available in English. For translations of the previous edition, see 'previous editions', below.

1. Dates shown are dates of first publication on this website.

Translation

Translation into other languages is encouraged for members of Eurachem. Other offers of translation should be directed to the Eurachem Secretariat for permission. The Eurachem policy on maintenance and development of Eurachem guidance, available on the Policies page, gives further information on translation.

Previous editions

The first edition of this information leaflet can be found here, in our publication archive. Selected translations of the first edition are listed below for convenience pending translation of the second edition.

1. Amended April 2017

Selecting the right proficiency testing scheme for my laboratory

Content

EURACHEM through its Proficiency Testing Working Group has produced an information leaflet to help laboratories select the most appropriate proficiency testing schemes. Several PT schemes are often available for the same area of testing, so this leaflet focuses on key questions that can help laboratories choose those PT schemes that are best suited for their needs.

This second edition updates the leaflet to reference current guidance on PT.

Availability

The second edition is currently available in the following languages. Links to translations of the first edition, available in 14 languages, are temporarily maintained on this page (below) for convenience while translations of the second edition are prepared.

Translation

Please consult the PT Working Group Chair if you would like to prepare a translation in your own language.

 

Previous editions

The first edition of this information leaflet can be found here, in our publication archive. Selected translations of the first edition are listed below for convenience pending translation of the second edition.

Notes

1. Dates show date of publication of the linked file on this website.

2. 2nd English edition first published 2022-07-30

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Using repeated measurements to improve the standard uncertainty

Content

Analysts often take multiple observations, and sometimes average the result of several observations to reduce the uncertainty associated with random variation. However, it is often unclear how the standard uncertainty associated with averaged results should be calculated from an observed standard deviation. Sometimes one should divide by the square root of the number of observations; sometimes the standard deviation is used unchanged, and sometimes some alternative formula is appropriate. 

This information leaflet has been prepared by the Eurachem Measurement Uncertainty and Tracability Working Group (see here for details) to give further explanation of when the classical 'root n' formula can, and can not, be used. The leaflet amplifies principles described in the Eurachem Guide "Quantifying uncertainty in analytical measurement", which is available here.

 

Availability

*2015 edition

Translation

Translation into other languages is encouraged for members of Eurachem. Other offers of translation should be directed to the Eurachem Secretariat for permission. The Eurachem policy on maintenance and development of Eurachem guidance, available on the Policies page, gives further information on translation.

Amendment history

This leaflet was amended to improve clarity in April 2016. The previous English version, as issued in 2015, is available for comparison.

Treatment of an observed bias

Content

bias img 240x194Bias is routinely determined during the validation of analytical methods. Usually, the observed bias is not exactly zero. It is then important to decide whether the observed bias can reasonably be treated as unimportant, or whether some further action needs to be taken. This can be particularly difficult to decide when applying the principles of the 'Guide to the Expression of Uncertainty in measurement', which assumes that a correction has been applied for any important bias. 

This information leaflet has been prepared by the Eurachem Measurement Uncertainty and Tracability Working Group (see here for details). The leaflet discusses whether or not an observed significant bias should be corrected and the impact this may have on the measurement uncertainty (MU). The leaflet does not describe how to apply a correction or how to increase the uncertainty to take account of an uncorrected bias, though it does provide relevant literature sources.

 

Availability

 * 2nd printing; editorial amendment only

Translation

Translation into other languages is encouraged for members of Eurachem. Other offers of translation should be directed to the Eurachem Secretariat for permission. The Eurachem policy on maintenance and development of Eurachem guidance, available on the Policies page, gives further information on translation.

Publication date

This leaflet was first published in English on 2017-05-27.

* The English copy on this page is a minor (editorial) amendment, published 2022-10-21; the recommendations are unchanged.