Quality

Quality refers to the inherent or distinctive characteristics or properties of a person, object, process or other thing. Such characteristics or properties may set a person or thing apart from other persons or things, or may denote some degree of achievement or excellence. When used in relation to people, the term may also signify a personal character or trait.

The term is sometimes contrasted with the concept of quantity. In science, the work of Aristotle focused on measuring quality, whereas the work of Galileo resulted in a shift towards the study of quantity.

In manufacturing

In manufacturing, "quality" means on target with minimum variation. Many different techniques and concepts have been tried to minimize defects in products, including SPC, Zero Defects, Six Sigma, quality circles, TQM and continuous improvement.

Most of these techniques and concepts are controversial to one degree or another, since there are two opposing schools of thought with regard to quality. One school subscribes to a statistical approach to quality, measuring variation and then taking corrective action. The other school subscribes to a more organic approach, arguing that one should "design in quality" rather than trying to "test in quality".

Historical development of the concept

The meaning for the term quality has developed over time. Five distinctive interpretations:

1. "Conformance to specifications" (Phil Crosby in the 1980s). The difficulty with this is that the specifications may not be what the customer wants; Crosby treats this as a separate problem.
2. "Fitness for use" (Joseph M. Juran). Fitness is defined by the customer.
3. A two-dimensional model of quality (Noriaki Kano and others). The quality has two dimensions: "must-be quality" and "attractive quality". The former is near to the "fitness for use" and the latter is what the customer would love, but has not yet thought about. Supporters characterise this model more succinctly as: "Products and services that meet or exceed customers' expectations". One writer believes (without citation) that this is today the most used interpretation for the term quality.
4. "Value to some person" (Gerald M. Weinberg)
5. (W. Edwards Deming), "Quality is pride of workmanship." See http://www.deming.org/

In music

In music quality refers primarily to the timbre, but also dynamics and musical texture, of a section or piece.

In phonetics

In phonetics quality refers to the articulatory features that distinguish vowels and to their acoustic correspondent. Vowel quality is opposed to vowel quantity.

See also

• ISO 9000
• Quality Management System
• Quality time
• Quality control
• Six Sigma
• Total Quality Management
• Metaphysics of Quality from Zen and the Art of Motorcycle Maintenance and Lila: An Inquiry into Morals by Robert M. Pirsig
• Software quality
• Video quality

Finding related topics

• list of economics topics
• list of information technology management topics
• list of production topics

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