【精益英文】是PDCA循環,還是PDSA循環?

The PDCA or PDSA Cycle began as a series of steps within the world of product development. It wasn’t until much later did it become a method for process improvement. Let’s go through the history together.

PDCA管理循環，或者PDSA管理循環，屬於產品開發的一系列步驟，直到很久之後，PDCA管理循環才成為一個流程改善的工具。那麼，讓我們來回顧下它的歷史吧。

1.The Shewhart Cycle 休哈特循環

Dr. Walter Shewhart is best known for his development of statistical control. Back in 1939, Dr. Shewhart struggled with the current view of his time regarding quality and product development. He didn’t believe it was a linear model, but rather a cycle. In his words,

沃特-休哈特博士，因其本人開發出（質量）統計控制原理而聞名遐邇。回到1939年，休哈特博士正和當時涉及到質量與產品開發的觀點進行辯論，其本人並不認可當時在質量與產品開發方面的觀點，他認為應該是一個循環，而不是線性模式。用他的話，就是：

These three steps must go in a circle instead of in a straight line, as shown . . . It may be helpful to think of the three steps in the mass production process as steps in the scientific method. In this sense, specification, production, and inspection correspond respectively to making a hypothesis, carrying out an experiment, and testing the hypothesis. The three steps constitute a dynamic scientific process of acquiring knowledge.

三大步驟（specification規範、production生產，以及inspection檢驗）應該形成的是一個循環，而不是直線，如圖所示……在大規模生產中，將規範、生產與檢驗視為科學方法的三大步驟，可能確實會很有幫助。以此來看，規範、生產與檢驗，分別對應相應的假設，實施實驗，並且驗證假設，這三個步驟構成了一個動態獲取知識的科學過程。

In his mind, it looked like this:

在休哈特博士看來，以上三大步驟看起來應該是這樣的：

2.The Deming Wheel戴明環

Dr. Walter Shewhart’s student at the time was Dr. W. Edwards Deming. It was Deming who took the Shewhart Cycle and modified it. In 1950, while speaking to the Japanese Union of Scientists and Engineers (JUSE) regarding statistical quality control, Dr. Deming modified the Shewhart Cycle by adding a 4th step that he called – at the time – 「redesign through marketing research」. Historians believe that it was at that meeting the term 「Deming Wheel」 was born.

愛德華茲-戴明彼時正是沃特-休哈特博士的學生，正是戴明博士接受了休哈特循環，並對該循環進行了修改。1950時，戴明博士在日本科學家與工程師聯合會上做關於統計質量控制的講話時，對休哈特循環進行了修改，在其中添加了第四步，當時，用他的話說，就是「通過市場研究進行重新設計」。歷史學家們相信，正是在那次會議上，「戴明環」誕生了。

At that meeting, Dr. W. Edwards Deming discussed these steps:

在那次會議上，愛德華茲-戴明討論了這些步驟：

1) Design the product

設計產品

2) Make it and test in lab and production line

做出產品，在實驗室與生產線進行測試

3) Launch the product

推出產品

4) Test it in service via market research and user interviews

通過市場調研與用戶訪談的方式對產品服務進行測試

5) Redesign and improve the product given customer’s feedback

重新設計並改善產品，對顧客予以反饋

3. PDCA Cycle is Born PDCA管理循環誕生

According to Misaki Imai, Japanese executives took the Deming Wheel from that 1950 seminar and called it PDCA and took Deming’s steps (1-4) and codified it as Plan-Do-Check-Act.

根據Misaki Imai的說法，自1950年那次研討會起，日本的高管們便接受了戴明環，將之稱為PDCA，將戴明博士提出的上述步驟（1-4）編纂為Plan(計劃)-Do(實施)-Check(查核)-Act(處置)。

According to Imai, in the 1960’s, the what was initially the Deming Wheel was called PDCA by the Japanese. It evolved from a method to describe product development to become a method for process improvement.

根據Misaki Imai的說法，戴明環起初被日本人稱作PDCA管理循環，其從一種描述產品開發的方法演變成為一種過程改進的方法。

4. PDSA Cycle is Reborn PDSA管理循環重生

In 1986, Dr. W. Edwards Deming reintroduces the Shewhart Cycle and warned his audience that Plan-Do-Check-Act (PDCA) version is not accurate because the English definition for 「check」 means to 「hold back」. Deming continues by encouraging his audience to use Plan-Do-Study-Act (PDSA) and not the 「corruption PDCA」 4.

1986年，愛德華茲-戴明重新介紹了休哈特循環，並警告受眾PDCA管理循環並不準確，因為英文中的「check」的意思是「控制」。戴明博士繼續鼓勵他的受眾去使用PDSA管理循環，而不是去使用變體-「PDCA」四大步驟。

5. PDCA or PDSA? 到底是PDCA管理循環，還是PDSA管理循環？

I’m not picking sides. I』ve always used PDCA. In fact, at Toyota PDCA is the recognized and approved framework, not PDSA. I’m not sure if that matters. I think in the grand scheme of things, in practice it really doesn’t matter. But, to theoreticians and academics, they will likely continue to quibble over PDCA versus PDSA. But for practitioners like you and me, we』ll be busy making things better.

我不會從中進行選擇，以往，我一直使用的是PDCA管理循環。事實上，在豐田公司，PDCA管理循環，而非PDSA管理循環，是被公認的，並且被認可的架構。真的不確定這是不是很重要！我相信，在宏觀上來看，在實踐時，真的沒那麼重要。但對於理論家與學者們而言，他們很可能會繼續使用PDCA去對抗PDSA，而對於你我這樣的實踐者而言，我們只會去忙著把事情做得更好。

What’s your opinion? Does it matter to you?

你怎麼看呢？對你而言，PDCA管理循環，還是PDSA管理循環，真的很重要嗎？

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