The 2nd round trial of 2017 conducted under the Task Force on Commercial Standardisation of Instrument Testing of Cotton (CSITC RT 2017-2) is complete and results have been distributed. CSITC round trials are now in their tenth year, a remarkable achievement in the long history of efforts to improve and standardise instrument testing of cotton.
Over the last five years, the median score on the combined properties evaluation has improved by about one-fifth, from 0.46 to 0.38. This indicates that the CSITC round trials are leading to systematic and sustained improvement in cotton quality testing around the world.
Average laboratory performance has improved remarkably in testing colour Rd (reflectance) and colour +b (yellowness), and there have also been improvements in testing micronaire, strength and length uniformity. However, the inter-instrument variation in tests for length is the same in 2017 as it was in 2012. Laboratory performance on parameters other than colour started from better levels, and so there has been less room for improvement.
Testing facilities submitted results from 124 instruments during RT 2017-2. Each round trial consists of four samples prepared by the US Department of Agriculture (USDA) and sent to participating laboratories. Each sample is tested in each laboratory six times a day for five days for all six CSITC parameters of micronaire, length, length uniformity, strength, Rd and +b, resulting in a total of 720 measurements from each instrument. Results are downloaded electronically and sent to the Bremen Fibre Institute (FIBRE) for evaluation. Because of the large number of observations over a five-day period, the resulting pattern of results can be used for detailed diagnostic evaluation.
Laboratories are not given grades or pass/fail results, and all results are confidential. The purpose of CSITC round trials are to facilitate improvements in both accuracy and precision among cotton testing laboratories around the world.
Laboratories are given an overall ranking, as well as rankings for performance on each of the six parameters. Rankings are based on the results of each lab in coming closest to the mean (average) values for all laboratories participating in the round trial on all six parameters.
The range of scores for the combined properties evaluation among the 124 instruments was 0.13 to 1.68 (a score of zero would be perfect), and the median overall evaluation of combined properties was 0.38.In addition to the six parameters for ranking, an additional four parameters were included for information purposes: short fibre index (SFI), maturity, trash area and trash count. The inter-laboratory variations for the four additional parameters are higher than the variations for the six parameters approved by CSITC. Therefore, laboratories are not evaluated according to the optional parameters. Nevertheless, the resulting deviations for each parameter provide useful information to market participants.
Since 2012, the standard deviation of inter-instrument test results for maturity and SFI have fallen (meaning they improved) by nearly half, and the measurement of trash count improved by about one-fourth. Inter-instrument variation in the measurement of trash area is about the same in 2017 as it was in 2012. The inter-instrument variations for maturity and SFI have improved to such an extent that the task force on CSITC will consider adding these parameters to the list of official CSITC parameters at its next meeting on August 25 in Memphis.
Laboratories are also being informed as to what proportion of their test results are within a given limit for each parameter. This information provides additional practical information that will be useful in improving testing performance. (SV)
Fibre2Fashion News Desk – India
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