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Quality in everyday life and business, engineering and manufacturing has a pragmatic interpretation as the non-inferiority, superiority or usefulness of something. This is the most common interpretation of the term.

Many different techniques and concepts have evolved to improve product or service quality, including SPC, Zero Defects, Six Sigma, Malcolm Baldrige National Quality Award, quality circles, TQM, Theory of Constraints (TOC),Quality Management Systems (ISO 9000 and others) and continuous improvement.

The meaning for the term quality has developed over time. Various interpretations are given below:

1. ISO 9000 - "Degree to which a set of inherent characteristic fulfills requirements"
2. (Philip B. Crosby in the 1980s)- "Conformance to requirements". The difficulty with this is that the requirements may not fully represent customer expectations; Crosby treats this as a separate problem.
3. (Joseph M. Juran).- "Fitness for use". Fitness is defined by the customer.
4. (Noriaki Kano and others)- A two-dimensional model of quality. 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 characterize this model more succinctly as: "Products and services that meet or exceed customers' expectations".
5. (Gerald M. Weinberg)- "Value to some person".
6. (W. Edwards Deming)- "Quality and the Required Style of Management" 1988 See http://www.deming.org/. "Costs go down and productivity goes up, as improvement of quality is accomplished by better management of design, engineering, testing and by improvement of processes. Better quality at lower price has a chance to capture a market. Cutting costs without improvement of quality is futile."
7. (Genichi Taguchi). "The loss a product imposes on society after it is shipped". Taguchi's definition of quality is based on a more comprehensive view of the production system.
8. Energy quality, associated with both the energy engineering of industrial systems and the qualitative differences in the trophic levels of an ecosystem.
9. One key distinction to make is there are two common applications of the term Quality as form of activity or function within a business. One is Quality Assurance which is the "prevention of defects", such as the deployment of a Quality Management System and preventative activities like FMEA. The other is Quality Control which is the "detection of defects", most commonly associated with testing which takes place within a Quality Management System typically referred to as Verification and Validation.

American Society for Quality Source: http://www.asq.org/glossary/q.html. "a subjective term for which each person has his or her own definition. In technical usage, quality can have two meanings:

1. the characteristics of a product or service that bear on its ability to satisfy stated or implied needs.
2. a product or service free of deficiencies."

The quality of a product or service refers to the perception of the degree to which the product or service meets the customer's expectations. Quality has no specific meaning unless related to a specific function and/or object. Quality is a perceptual, conditional and somewhat subjective attribute.

The dimensions of quality refer to the attributes that quality achieves in Operations Management

• Quality supports dependability
• Dependability supports Speed
• Speed supports Flexibility
• Flexibility supports Cost.

Quality <-> Dependability <-> Speed <-> Flexibility <-> Cost

In the manufacturing industry it is commonly stated that “Quality drives productivity.” Improved productivity is a source of greater revenues, employment opportunities and technological advances. Most discussions of quality refer to a finished part, wherever it is in the process. Inspection, which is what quality insurance usually means, is historical, since the work is done. The best way to think about quality is in process control. If the process is under control, inspection is not necessary.

However, there is one characteristic of modern quality that is universal. In the past, when we tried to improve quality, typically defined as producing fewer defective parts, we did so at the expense of increased cost, increased task time, longer cycle time, etc. We could not get fewer defective parts and lower cost and shorter cycle times, and so on. However, when modern quality techniques are applied correctly to business, engineering, manufacturing or assembly processes, all aspects of quality - customer satisfaction and fewer defects/errors and cycle time and task time/productivity and total cost, etc.- must all improve or, if one of these aspects does not improve, it must at least stay stable and not decline. So modern quality has the characteristic that it creates AND-based benefits, not OR-based benefits.

The most progressive view of quality is that it is defined entirely by the customer or end user and is based upon that person's evaluation of his or her entire customer experience. The customer experience is the aggregate of all the touch points that customers have with the company's product and services, and is by definition a combination of these. For example, any time one buys a product one forms an impression based on how it was sold, how it was delivered, how it performed, how well it was supported etc.

• Quality Management
• Quality control
• W. Edwards Deming
• Six Sigma
• Total Quality Management
• Theory of Constraints
• ISO 9000
• Software quality
• Video quality
• Quality Engineering
• Quality of Life
• Metaphysics of Quality

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

• A proposed universal definition of 'quality'
• DocQuality Document references on quality theme
• Quality Management links