Statistical Treatment, Reports, and Supporting Documents

Statistical Procedures and Approaches

• Magruder Proficiency Testing Program Statistics Documentation (pdf)
• The International Harmonized Protocol for the Proficiency Testing of Analytical Chemistry Laboratories (IHP, 2006)
• Statistical methods for use in proficiency testing by interlaboratory comparison (ISO 13528:21022)

Examples of Reports

Here are examples of Report Cards and the Master Lists for all the data derived from a single sample:

• Example of a Proficiency Test Report Card for a lab (pdf)
• Example of an Individual Method Proficiency Test Report Card for a lab (pdf)
• Example of Analyte All Tests Report (pdf)
• Example of Method All Tests Report (pdf)
• Example of Analyte Statistical Summary (pdf)
• Example of Individual Method Performance Summary (pdf)

Sample Homogeneity and Stability Evaluation:

Here are presentations on sample homogeneity and stability monitoring. Of particular interest is a pseudo homogeneity/stability check we have established for every sample.

• Homogeneity Monitoring (pdf)
• Stability Monitoring (pdf)

Documents Published by the Analytical Methods Committee of The Royal Society of Chemistry:

Here are selected short supporting documents. There is a great deal of literature describing the applications of Robust Statistics over an extremely diverse range of subjects. John Tukey, Peter Huber and Frank Hampel have been credited with founding the discipline and all this since the landmark paper by Tukey in 1960. So, you can see that this is a fairly young science nevertheless, the literature and bookshelves are rife with the subject.

• Analytical Methods Committee 2 page Technical Brief describing the Robust Calculations used in the IHP and ISO 13528 (pdf)
• Analytical Methods Committee 2 page Technical Brief on representing data distributions with kernel density estimates (pdf)
• Analytical Methods Committee 2 page Technical Brief describing and using the "Fitness for Purpose" criterion (pdf)
• Analytical Methods Committee 2 page Background Paper "What is proficiency testing?" (pdf)
• Analytical Methods Committee 2 page Technical Brief describing Creating your own ffp criteria (pdf)
• Analytical Methods Committee 5 page report on "Robust Statistics - How Not to Reject Outliers", 1989 (pdf)
• Analytical Methods Committee 2 page Technical Brief on "The amazing Horwitz function" (pdf)

Interesting Articles:

• Short 3 page philosophical description of Robust Statistics by Frank Hampel (2001) (pdf)
• Short 3 page description of the historical development of Robust Statistics by Elvezio Ronchetti (2006) (pdf)

Pertinent references to which open access cannot be provided:

• "Robust Estimation and Hypothesis Testing", 2nd Ed., Rand R. Wilcox, 2005, Elsevier
• "Robust Statistics", 2nd Ed., P.J. Huber and E.M. Ronchetti, 2009, Wiley
• "Robust Statistics: The Approach Based on Influence Functions", F.R. Hampel, E.M. Ronchetti, P.J. Rousseeuw and W.A. Stahel, 1986, Wiley
• "A survey of sampling from contaminated distributions", J.W. Tukey, (1960). In "Contributions to Probability and Statistics.", I. Olkin, S.G. Ghurye, W. Hoeffding, W.G. Madow and H.B. Mann (Eds), Stanford University Press, pp. 448-485