Sampling Column

What is the meaning of analysing any sample if it cannot be documented to be representative? The answer is “none”, and that is the reason for this column. Starting with the Theory of Sampling, it will build into a valuable resource covering the theory and practice of representative sampling.

The Sampling Column is edited by:

Kim-EsbensenKim H. Esbensen
originally trained as a geologist/geochemist, but it was 30 years before he actually worked in a geoscience institution (The Geological Survey of Denmark and Greenland). In-between he established two research groups dealing with PAT and chemometrics. He found a third love, scientifically speaking, some 15 years ago, when he met the Theory of Sampling (TOS), and the field of representative sampling has occupied his career ever since. Kim is specifically interested in the interaction between process—and material heterogeneity, representative sampling and augmented measurement uncertainty.

Claas-WagnerClaas Wagner
Originally trained as an economist, Claas Wagner realised that his real interests were with environmental and energy related topics and therefore continued his education in this direction. Sustainable resource management, emission reduction procedures and energy efficiency issues have all one common ground: decisions need to be based on valid data. This led to Claas’ PhD on representative sampling and data analysis for quality monitoring in large-scale combustion plants. Currently Claas combines his fields of interest, working as a consultant for various industries providing quality assurance approaches. Throughout all of this reigns representative sampling. 

Into the laboratory… TOS still reigns supreme

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Sampling_28-6_F7-sKim Esbensen and Claas Wagner continue to stress that grab sampling is still an absolute no-no regardless of the size of the sampling device or the sample.

Read more: Into the laboratory… TOS still reigns supreme

 

Spear sampling: a bane at all scales

Sampling_28-5-sThis column now turns its attention to sampling using a very popular tool, the “sampling spear”. There is much good to be said about spear sampling—and only one thing which is bad. But this is bad enough: spear samplers are very, very difficult to get to produce representative samples! The spear sampling principle can be made representative, but in most practical situations in which spear sampling is used today it manifestly is not. WHY? And more importantly, WHAT can be done about it? This column also turns out to touch on one of TOS’ six governing principles: SSI, Sampling Scale Invariance.

Read more: Spear sampling: a bane at all scales

 

There are standards—and there is THE standard

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In their Sampling Column, Kim Esbensen and Claas Wagner stray into Quality Matters territory as they look at standards and how they work with the Theory of Sampling. Kim and Claas are concerned that many international standards do not comply with the TOS and that this compromises the results.

Read more: There are standards—and there is THE standard

   

Sampling quality criteria (SQC)

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Another side of ensuring that our results are valid is correct sampling. In the latest Sampling Column on “Sampling quality criteria (SQC)” Kim Esbensen and Claas Wagner continue our education in the use of the Theory of Sampling. The fundamental step in ensuring representative sampling is sampling quality criteria, and the authors describe why and how.

Read more: Sampling quality criteria (SQC)

 

Sampling quality assessment: the replication experiment

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In the Sampling Column, Kim Esbensen and Claas Wagner continue our education about representative sampling. In “Sampling quality assessment: the replication experiment”, they provide an overview of the issue of replication, which may not be as straightforward as might be expected at first.

Read more: Sampling quality assessment: the replication experiment

   

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