Quality

The term quality is used to refer to the desirability of properties or characteristics of a person, object, or process. In the case of a person, this is considered in a particular context, such as worker, student, sportsperson, etc. The term is often used in opposition to 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 is the concept of making products fit for a purpose and with the fewest defects. Many different techniques and concepts have been tried to minimize defects in products, including Zero Defects, Six Sigma, and the House of Quality.

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 defects 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.

Four distinctive interpretations:

• “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.
• “Fitness for use” (Joseph Juran). Fitness is defined by the customer.
• 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.
• “Value to some person” (Gerald M. Weinberg)

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