Put quite simply, metrology is the science of measurement. In broad terms metrologists focus on developing and evaluating technologies and systems for objectively measuring the quality attributes of raw materials and manufactured products.

It is essential that raw materials and products meet the requirements of those who use them. This fitness for use defines their quality. There are two general aspects of quality: quality of design and quality of conformance.

Raw materials and products are generally available in various grades or levels of quality. These variations are often intentional, and consequently the appropriate technical term in such instances is quality of design. For example, all wool suits serve the same basic function, but they are available in a range of designs, fabrics and prices, aimed at specific market segments.

On the other hand, quality of conformance is how well the product conforms to the specifications and tolerances required by the design. Quality of conformance is influenced by a number of factors. Such as:

1. Variability of the greasy wool
2. Choice of the manufacturing processes
3. Operation of these processes
4. Training and supervision of the work force
5. Type of quality-assurance system (process controls, tests, inspection activities)
6. Extent to which these quality assurance systems are followed
7. Motivation of the workforce to achieve quality.

Every product, including wool, possesses a number of elements that jointly describe its fitness for use. These elements are often called quality characteristics. Quality characteristics may be of several types, for example:

• Physical: length, weight, fineness, yarn evenness
• Sensory: handle, feel, appearance, colour
• Time Orientation: reliability, durability, serviceability

Generally it is difficult (and expensive) to provide customers with raw materials and products that have flawless quality characteristics. There is a certain amount of variability inherent in any raw material or product and consequently any two products can never be truly identical. Wool is an extremely variable material. It varies along the fibre, between fibres, between staples, between animals, between mobs, between bloodlines and between regions.

Quality characteristics can be estimated subjectively using vision and touch, or they can be assigned a numerical value using objective measurements. Traditionally, the hand and the eye were the major tools used to determine the value and processing attributes of wool. Today however, at all levels of the industry, technology is increasingly replacing subjectivity.