Quality 是什么？

文章出處

通常，我們談及 Quality（質量）時，最常見的問題就是：Quality 是什么？

有很多業界先驅和研究人員已經回答了這個問題，我在這里并不會再給出一個新的答案。在學習總結了這些關于質量的定義后，可將問題的答案分為兩個陣營：

符合要求（Conformance To Requirements）：質量就是指產品或服務的可測量的屬性滿足一組固定的要求，也就是說，符合預先定義的要求。
滿足客戶需求（Meeting Customer Needs）：質量獨立于任何可測量的屬性，也就是說，質量就是指產品或服務滿足客戶預期的能力，無論是顯式的還是隱式的。

質量管理哲學

索引條目

Philip B. Crosby 的質量理論
Walter Edwards Deming 的質量理論
Armand Vallin Feigenbaum 的質量理論
Kaoru Ishikawa 的質量理論
Joseph Moses Juran 的質量理論
Walter Andrew Shewhart 的質量理論

Philip B. Crosby 的質量理論

在 Philip B. Crosby 的 “Quality is free: the art of making quality certain” 書中寫到：

The first erroneous assumption is that quality means goodness, or luxury or shininess. The word “quality” is often used to signify the relative worth of something in such phrases as “good quality”, “bad quality” and “quality of life” - which means different things to each and every person. As follows quality must be defined as “conformance to requirements” if we are to manage it. Consequently, the nonconformance detected is the absence of quality, quality problems become nonconformance problems, and quality becomes definable.

Crosby 很明確的將質量定義為 “Conformance to requirements” 。盡管如此，他也指出要嘗試盡可能的理解客戶的全部預期。同時，Crosby 也強調了清晰定義質量的可可測量和可管理的概念的重要性。

Crosby 關于質量管理的 4 項基本原則：

Quality is conformance to requirements
Quality prevention is preferable to quality inspection
Zero defects is the quality performance standard
Quality is measured in monetary terms – the price of non-conformance

Crosby 關于質量改進的 14 個步驟：

Management is committed to quality – and this is clear to all
Create quality improvement teams – with (senior) representatives from all departments.
Measure processes to determine current and potential quality issues.
Calculate the cost of (poor) quality
Raise quality awareness of all employees
Take action to correct quality issues
Monitor progress of quality improvement – establish a zero defects committee.
Train supervisors in quality improvement
Hold “zero defects” days
Encourage employees to create their own quality improvement goals
Encourage employee communication with management about obstacles to quality
Recognise participants’ effort
Create quality councils
Do it all over again – quality improvement does not end

Walter Edwards Deming 的質量理論

Walter Edwards Deming 在 “Out of the crisis: quality, productivity and competitive position” 一書中指出：

The problem inherent in attempts to define the quality of a product, almost any product, where stated by the master Walter A. Shewhart. The difficulty in defining quality is to translate future needs of the user into measurable characteristics, so that a product can be designed and turned out to give satisfaction at a price that the user will pay. This is not easy, and as soon as one feels fairly successful in the endeavor, he finds that the needs of the consumer have changed, competitors have moved in etc.

Deming 強調質量必須以滿足客戶為基準（也就是：“meeting customer needs”），概念上要比 “conformance to requirements” 更廣泛些。

Deming 的管理哲學強調組織內的每個人的主要人都就是滿足或超越客戶的需求。更進一步說，企業需要確保每個人對客戶的輸出的質量。

Deming 企業管理職能轉變的 14 條原則：

Create constancy of purpose for improvement of product and service.
Adopt the new philosophy.
Cease dependence on mass inspection.
End awarding business on price.
Institute training.
Institute leadership.
Drive out fear.
Break down barriers between departments.
Eliminate slogans, exhortations and numerical targets.
Eliminate numerical quotas or work standards.
Remove barriers to taking pride in workmanship.
Institute a vigorous programme of education.
Take action to accomplish the transformation.

Armand Vallin Feigenbaum 的質量理論

隨著全面質量控制的深淵影響，現在 “Feigenbaum” 和 “Total Quality Control” 幾乎變成了同義詞。

Armand Vallin Feigenbaum 是這樣描述他對質量控制的觀點的：

Quality is a customer determination, not an engineer’s determination, not a marketing determination, nor a general management determination. It is based on upon the customer’s actual experience with the product or service, measured against his or her requirements – stated or unstated, conscious or merely sensed, technically operational or entirely subjective – and always representing a moving target in a competitive market. Product and service quality can be defined as: The total composite product and service characteristics of marketing, engineering, manufacture and maintenance though witch the product and service in use will meet the expectations of the customer.

很顯然，Feigenbaum 關于質量的定義毋庸置疑也是 “meeting customer needs”。而事實上，他也充分強調同時滿足客戶的實際需求和預期需求的重要性，也就是說滿足要同時滿足客戶的顯式需求和隱式需求。

Kaoru Ishikawa 的質量理論

Kaoru Ishikawa 在他的書 “What is quality control? The Japanese Way” 中寫道：

We engage in quality control in order to manufacture products with the quality which can satisfy the requirements of consumers. The mere fact of meeting national standards or specifications is not the answer, it is simply insufficient. International standards established by the International Organization for Standardization (ISO) or the International Electrotechnical Commission (IEC) are not perfect. They contain many shortcomings. Consumers may not be satisfied with a product which meets these standards. We must also keep in mind that consumer requirements change from year to year and even frequently updated standards cannot keep the pace with consumer requirements. How one interprets the term “quality” is important. Narrowly interpreted, quality means quality of products. Broadly interpreted, quality means quality of product, service, information, processes, people, systems etc. etc.

Ishikawa 關于質量的觀點也符合 “meeting customer needs” 的定義。他強調質量是一個動態的概念，質量會隨著客戶需求和預期的改變保持持續的變化。

Joseph Moses Juran 的質量理論

在 “Jurans’s Quality Control Handbook” 一書中，Joseph M. Juran 指出了兩點質量的涵義：

The word quality has multiple meanings. Two of those meanings dominate the use of the word:
1) Quality consists of those product features which meet the need of customers and thereby provide product satisfaction.
2) Quality consists of freedom from deficiencies. Nevertheless, in a handbook such as this it is most convenient to standardize on a short definition of the word quality as “fitness for use”.

Juran 關于質量的定義，與前面幾位質量大師有幾分區別。他的觀點是，我們不能使用 “Quality” 這個詞來包含滿足客戶需求或預期，因為它太難實現了。取而代之的是，使用 “fitness for use” 來描述需求和產品屬性。看起來，Juran 的質量定義可以解釋成 “conformance to requirements” 而不是 “meeting customer needs”。

Juran 的質量管理三部曲：

Quality Planning
Quality Control
Quality Improvement

Walter Andrew Shewhart 的質量理論

Walter A. Shewhart 在 “Economic control of quality of manufactured product” 一書中定義了質量：

There are two common aspects of quality: One of them has to do with the consideration of the quality of a thing as an objective reality independent of the existence of man. The other has to do with what we think, feel or sense as a result of the objective reality. In other word, there is a subjective side of quality.

盡管 Shewhart 關于質量的定義始于19世紀20年代，但其仍被認為是非常優秀的定義。Shewhart 談到了質量的主觀性和客觀性，所以很合理的同時滿足了 “conformance to requirements” 和 “meeting customer needs”。