Washington, DC
October 8, 2007
Source:
International Cotton Advisory
Committee
The third Round Trial conducted
under the auspices of the Task Force on Commercial
Standardization of Instrument Testing of Cotton (CSITC RT
2007-3) was conducted during August and September 2007. 54
testing facilities with 69 instruments participated.
Participating testing centers were located in Africa, Asia,
Australia, Europe, North America, and South America. Five cotton
samples with known values were mailed to each participating
laboratory in August. Each laboratory tested each sample six
times each day for five days. Each sample was tested for the six
CSITC parameters of length, length uniformity index, micronaire,
strength, Rd (reflectance) and +b (yellowness).
All five of the samples were from upland saw ginned cotton.
Laboratory results were collected by USDA and forwarded to the
Bremen Fibre Institute for evaluation. Laboratories were given
an overall ranking, as well as rankings for performance on each
of the six tests. Rankings were 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 are confidential, but each testing
facility receives 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.
Rankings were based on the results of each lab in coming closest
to the mean values for all laboratories participating in the
Round Trial on all six measurements. The range of scores for the
combined properties among the 69 instruments was 0.25 to 2.28 (a
score of zero would be perfect), and the median overall
evaluation of combined properties was 0.47. The results in CSITC
RT 2007-3 are highly consistent with the results from RT 2007-1
and RT 2007-2. The average difference between the evaluation
grades of identical instruments in comparison between RT 2007-1,
RT 2007-2 and RT 2007-3 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 2007-3
|
Property |
Standard Deviation
based on Single Tests |
Standard Deviation
based on 30 Tests/Sample |
|
Micronaire |
0.09 mic |
0.08 mic |
| Strength
|
1.44
g/tex |
1.18
g/tex |
| Length
|
0.017
inches |
0.011
inches |
| Length
Unif. |
0.79
units |
0.48
units |
| Color Rd
|
1.14
units |
1.05
units |
| Color +b
|
0.40
units |
0.36
units |
Summary Tables Available on the
Web
Summary tables from the first three 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 by having 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).
Round Trial Cost & Sign-Up
Participation in the CSITC Round Trial is subsidized by USDA and
the Bremen Fibre Institute, but a nominal fee of US$75 per
quarter, 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: 202-463-6950
66th ICAC Plenary Meeting
The work of the Task Force on CSITC will be discussed during the
66th Plenary Meeting of the ICAC in Izmir, Turkey, during 22-26
October 2007. The Task Force consists of 18 members representing
all segments of the world cotton industry. The Task Force will
meet on Sunday afternoon 21 October in the Hilton Hotel in
Izmir. Observers are welcome, but observers must notify the ICAC
Secretariat of their interest by sending an E-mail to
CSITCsecretariat@icac.org.
The International Cotton
Advisory Committee is an association of 41 governments of
cotton producing and consuming countries. The Secretariat of the
Committee publishes information related to world cotton
production, supply, demand and prices, and provides technical
information on cotton production technology |
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