The 2nd Round Trial of CSITC 2017 was completed at the end of June 2017

Date Posted: 12 Jul, 2017

From the Secretariat                                                                                
CSITC ROUND TRIALS IN THEIR TENTH YEAR
 
The 2nd Round Trial of 2017 conducted under the auspices of the Task Force on Commercial Standardization of Instrument Testing of Cotton (CSITC RT 2017-2) was completed at the end of June 2017, 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 standardize instrument testing of cotton.
 
Improvement
 
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 color Rd (reflectance) and color +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 color started from better levels, and so there has been less room for improvement.
 
Round Trial Procedures
 
Testing facilities submitted results from 124 instruments during RT 2017-2. Each round trial consists of four samples prepared by the U.S. 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.
 
Typical inter-Instrument variation, given as standard deviations:
 
CSITC RT 2017-2
 
Property Standard Deviation
based on Single Tests
Standard Deviation
based on 30 tests/sample
Micronaire 0.071 mic 0.058 mic
Strength 0.953 g/tex 0.687 g/tex
Length 0.0155 inches 0.0108 inches
Length Unif. 0.716 units 0.400 units
Color Rd 0.588 units 0.489 units
Color +b 0.318 units 0.268 units
 
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.
 
Optional Parameters
 
In addition to the 6 parameters for ranking, an additional 4 parameters were included for information purposes: Short Fiber Index (SFI), Maturity, Trash Area and Trash Count. The inter-laboratory variations for the four additional parameters are higher than the variations for the 6 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.
 
The typical inter-Instrument variation, given as standard deviations:
 
CSITC RT 2017-2
 
Property Standard Deviation
based on Single Tests
Standard Deviation
based on 30 tests/sample
Trash Count 6.26 5.39
Trash Area 0.055% 0.043%
Maturity 1.61 units 1.55 units
SFI 1.27 units 1.10 units
 
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.
 
Within-Limits Evaluations
 
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.
 
Average Percentage of Instruments Testing Within Established Limits:
 
CSITC RT 2017-2
 
Property Limit chosen by CSITC Average % of results inside the limits % of instruments with all sample results inside the limits Average % of results inside the limits % of instruments with 95% of sample results inside the limits
    based on 30 tests/sample based on 30 tests/sample based on 1 test/sample based on 1 test/sample
Micronaire 0.20 units 100 100 98.8 92.7
Strength 2.0 g/tex 97.2 88.7 94.4 66.9
Length 0.030 inches 99 96 96 75.8
Length Unif. 2.0 units 98.2 96 97 91.1
Color Rd 1.5 units 92.9 90.2 92.3 83.7
Color +b 0.5 units 91.1 75.6 85.5 40.7
 
 
Information about CSITC and overall Round Trial results (information for individual laboratories is confidential) is available at www.CSITC.org.
 
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