Inspection

Inspection is one of the original techniques of quality which simply means to look at things. It may seem trivial, but as Yogi Berra said, 'You can observe a lot by watching'.

Shigeo Shingo identified three different types of inspection:

Judgment inspection means spotting the defects in the completed product, which is sometimes referred to as 'inspecting in the quality.'
Informative inspection uses data gained from inspection to control the process and prevent defects, for example by using SPC.
Source inspection is what Shingo thought of as 'proper' inspection as it aims to determine whether the conditions necessary for producing quality products exist before any work even begins. It is thus concerned with such principles as capability. He said, "It had dawned on me that the occurrence of a defect was the result of some condition or action, and that it would be possible to eliminate defects entirely by pursuing the cause".

Note that the term source inspection is also used for inspections carried out at a supplier's premises.

Fagan Inspections is a method devised by Michael Fagan at IBM for inspecting software programs, designs and other detailed documentation. It is a moderated method in which the inspection work is divided up, all material are carefully provided and a meeting used only for reporting and clarifying detail (thus protecting the ego of the original author).

Average Incoming Quality is the average assessed value from inspection of inputs. Average Outgoing Quality is the average assessed value of outputs.

Inspection

See also: