Washington, DC
January 2, 2008
Source:
International Cotton Advisory
Committee
The fourth Round Trial conducted
under the auspices of the Task Force on Commercial
Standardization of Instrument Testing of Cotton (CSITC RT
2007-4) was conducted during November and December 2007. 58
testing facilities with 79 instruments participated.
Participating testing centers were located in Africa, Asia,
Australia, Europe, North America, and South America. In each
Round Trial, five cotton samples with known values are mailed to
each participating laboratory. Each laboratory tests each sample
six times each day for five days, for a total of 150 tests. Each
sample is tested for the six CSITC parameters of length, length
uniformity index, micronaire, strength, Rd (reflectance) and +b
(yellowness). Accordingly, 900 separate test results (150 tests
of 6 parameters) from each instrument are evaluated.
In the fourth Round Trial, all five of the samples were from
upland saw ginned cotton.
Laboratory results for each Round Trial are collected by USDA
and forwarded to the Bremen Fibre Institute for evaluation.
Laboratories are given an overall ranking, as well as rankings
for performance on each of the six parameters. Rankings are
based on the first four upland cotton samples with known values.
The purpose of the fifth cotton sample in all CSITC Round Trials
is for special study purposes and is not used for
performance-ranking.
The names and results from each test center participating in the
Round Trials in 2007 were confidential, but each testing
facility received an evaluation of its performance in the Round
Trial and a detailed diagnostic analysis of results. The purpose
of the CSITC Round Trial is to facilitate improved performance,
and the large number of tests performed over five days makes
detailed diagnostic analysis possible.
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 measurements. The range of scores for the
combined properties among the 79 instruments was 0.21 to 1.99 (a
score of zero would be perfect), and the median overall
evaluation of combined properties was 0.49. The results in CSITC
RT 2007-4 are highly consistent with the results from the first
three Round Trials conducted in 2007. The average difference
between the evaluation grades of identical instruments in
comparison between the four Round Trials conducted during 2007
was 0.1, which means, that the evaluation of each single testing
facility, and therefore its accuracy, is quite stable.
The typical inter-laboratory variations achieved by High Volume
Testing, given as standard deviations, were:
CSITC RT 2007-4
|
Property |
Standard Deviation
based on Single Tests |
Standard Deviation
based on 30 Tests/Sample |
|
Micronaire |
0.10 mic |
0.08 mic |
|
Strength |
1.35 g/tex |
1.02
g/tex |
|
Length |
0.017 inches |
0.010
inches |
|
Length Unif. |
0.82 units |
0.51
units |
|
Color Rd |
1.07 units |
1.04
units |
|
Color +b |
0.40 units |
0.34
units |
Summary Tables Available on the
Web
Summary tables from the first four CSITC Round Trials are
available on the web site:
www.ICAC.org.
The summary includes:
- Inter-laboratory averages
and variability and in-laboratory variability for each of
the 6 properties and each of the five cotton samples.
- Graphs showing the
distributions for every property and each cotton.
- A summary list of the
combined properties evaluations.
- A summary list of the
evaluations for each property.
Benefits of Participation
Participants in CSITC Round Trials benefit from detailed
feedback that can be utilized to demonstrate measurement
performance to customers and to address measurement related
problems. Results will confirm the participant's ability to
provide reproducible test measurements that are based on the
established international standard. In addition, participation
is a recommended practice for fulfilling quality management
requirements in laboratories (e.g. ISO 17025).
The CSITC Round Trials complement, but do not replace, the
Bremen Cotton Round Trial and the USDA HVI Checktest.
Participation in CSITC Round Trials provides numerous benefits:
- Statistically robust
evaluations of instrument performance based on 4 cottons
and 30 tests per cotton during each Round Trial,
- An overall rating of
test center accuracy in comparison with elite testing
facilities worldwide,
- Unique quarterly and
annual certificates of laboratory participation and
instrument ratings, and
- Detailed diagnostic
evaluations of instrument performance over a wide range
of parameter values.
Participation in the Bremen and
USDA programs remains meaningful, and the three programs are
mutually reinforcing. The Bremen Round Trial is not limited to
High Volume Testing and allows evaluation of all cotton testing
instruments free of cost. The USDA HVI Checktests are conducted
monthly, rather than quarterly.
Round Trial Cost & Sign-Up
Participation in the CSITC Round Trial is subsidized by USDA,
the Bremen Fibre Institute and the ICAC Secretariat. Support is
also received from the Common Fund for Commodities and the
European Commission through the CFC/ICAC/33 project. A nominal
fee of US$300 per year for four trials is charged to cover
expenses associated with sample distribution.
To participate in future CSITC Round Trials, contact:
International Cotton
Advisory Committee - CSITC
Email:
CSITCsecretariat@icac.org
Fax: +1 202 463 6950
9th CSITC Meeting
The Task Force on CSITC will meet on Wednesday, April 2, 2008 in
Bremen Germany in conjunction with a meeting of the
International Textile Manufacturers Association (ITMF)
International Committee on Cotton Testing Methods. The Task
Force consists of 18 members representing all segments of the
world cotton industry. Observers are welcome, but observers must
notify the ICAC Secretariat of their interest by sending an
E-mail to
CSITCsecretariat@icac.org. |
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