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Development of a Regular CSITC Round Trial Axel Drieling

Development of a Regular CSITC Round Trial Axel Drieling Faserinstitut Bremen e.V. (Bremen Fibre Institute) - Laboratory of the Bremen Cotton Exchange - James L. Knowlton USDA, AMS, Cotton Program Memphis, TN Beltwide Cotton Conferences New Orleans, LA, January 9-12, 2006

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Development of a Regular CSITC Round Trial Axel Drieling

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  1. Development of a Regular CSITC Round Trial Axel Drieling Faserinstitut Bremen e.V. (Bremen Fibre Institute) - Laboratory of the Bremen Cotton Exchange - James L. Knowlton USDA, AMS, Cotton Program Memphis, TN Beltwide Cotton Conferences New Orleans, LA, January 9-12, 2006 Cotton Quality Measurements Conference

  2. ICAC Task Force on Commercial Standardization of Instrument Testing of Cotton, formed in December 2003 15 international members: cotton exporters, importers, all segments of the world cotton industry and research Based on the consensus that instrument testing is superior to traditional hand classing Objective: Introduction of a worldwide acceptable, adoptable and reliable instrument based cotton quality assessment with defined test rules based on reliable instrument test results based on a worldwide cotton testing laboratory evaluation system Options for instrument testing Fixed calibration with Universal Standard Material (HVICCS etc.) Choice of suitable parameters: at present Mic, Strength (HVICCS), Length (UHML HVICCS), Uniformity Index, Color Rd and Color +b Only / All instruments are suitable that conform to Universal Standard Material results for the chosen parameters that do not show systematic deviation that do not show extended result variability CSITC Task Force

  3. It is essential to check the reliability of cotton testing laboratories and the test results provided by the laboratories Round Trial results will allow the laboratories to demonstrate their capability to meet recommended standards, but certification cannot guarantee the accuracy of individual tests Round Trial results will help laboratories to achieve more accurate results CSITC Round Trial (Participation in the CSITC Round Trial is anonymous and individual results will only be given to the individual participant)

  4. Wording is chosen based on ISO 5725 Trueness refers to the closeness of agreement between the arithmetic mean of a large number of test results (of one laboratory) and the accepted reference value Precision refers to the closeness of agreement between (single) test results / variability of instrument results on tested cottons Accuracy includes trueness and precision Excursion: Definitions / Wording

  5. Attributes of Different International Round Trials

  6. Evaluation of the test methods / Test result variability inter-laboratory variability in-laboratory variability possbible additions: variations between instrument types etc. Evaluation / rating of the participating laboratories- based on the trueness of the results - Detailed analysis of laboratory results to achieve more accurate results- based on trueness and precision - Aims of the CSITC Round Trial

  7. Configuration of the Round Trial Tests Only cotton 1 to cotton 4 are used to evaluate laboratories Cotton 5 offers the chance to include cottons with different behavior / from different origins

  8. Laboratory results are compared to reference results based on the interlaboratory average of the participating laboratories In case that the number of participating laboratories is not satisfactory to calculate reliable reference results, the USDA Established Results will be added for consideration Possibilities for the consideration of outliers No exclusion of outliers 90% trimmed mean (exclusion of 5% of the lowest and 5% of the highest results) Statistical detection of outliers: (e.g.) Grubbs Method Grubbs Method was chosen, as only a statistical detection of outliers allows both: to calculate a reference result that is not influenced by outliers and to calculate inter-laboratory variability results that are not systematically biased Basis: Reference Results

  9. Excursion:Reference Results  Consideration of Outliers

  10. Excursion:Reference Results  Consideration of Outliers

  11. a) Test Result Variability • Exemplary inter-laboratory distributions of the results: • Micronaire for Cotton 1 • Based on 30 tests • Based on 6 tests on one day

  12. a) Test Result Variability

  13. a) Test Result Variability

  14. a) Test Result Variability

  15. a) Test Result Variability

  16. a) Test Result Variability

  17. a) Test Result Variability

  18. b) Evaluation / Rating of Each Participating Laboratoryfor the example of laboratory 115

  19. b) Evaluation / Rating of Each Participating Laboratoryfor the example of laboratory 115 Same kind of presentation is done for every single property

  20. c) Detailed Laboratory Analysisfor the example of laboratory 115 • Detailed Trueness Evaluation to find systematical deviations / biases

  21. c) Detailed Laboratory Analysisfor the example of laboratory 115 • Precision Evaluation to show / compare laboratory test result consistency/variability

  22. CSITC Round Trial Is based on the recommendations of the CSITC Task Force Was developed in co-operation between the Bremen Fibre Institute and USDA-AMS Is headed by the International Cotton Advisory Committee (ICAC) Will be conducted regularly in co-operation between the Bremen Fibre Institute and USDA-AMS Timetable 1. Pilot Round Trial was conducted in 2005 2. Pilot Round Trial was conducted in 2006, with 46 laboratories/instruments Regular Round Trials are starting now (2007-1) Samples are already shipped Approx. 60 laboratories will participate with approx. 90 instruments For registration in future Round Trials, please contact the ICAC Conclusion

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