What is the precision (repeatability) of wool testing?

The precision of an individual test result is usually expressed as Confidence Limits. Normally, the precision of a test result is defined in terms of 95% Confidence Limits, i.e., the limits on either side of the "true" result within which you can expect 95% of any repeat measurements to lie.

For example the 95% Confidence Limit for Laserscan measurement of Mean Fibre Diameter is ± 0.37microns for wools less than 26 microns and ± 0.66 microns for wools 26 micron and greater. The 95% Confidence Limit for Staple Length is ± 4.8 mm for fleece wool and ± 5.4 for non-fleece wools. For Staple Strength, the 95% Confidence Limit is ± 5.9 N/Ktex for both fleece and non-fleece wools.

Detailed information about precision is included in all IWTO Specifications. In some cases the precision varies with the magnitude of the parameter being measured (e.g. Woolbase, Vegetable Matter Base and Mean Fibre Diameter). For the LASERSCAN instrument (IWTO-12) the 95% Confidence Limits for Mean Fibre Diameter (MFD) are expressed in 5 micron increments as follows: