Inspection checklist

Deming's Point 3 of 14 - Cease dependence on inspection to achieve quality...

Deming's 3rd point is the first to mention quality, and it is specific, even if its implementation is sometimes a tall order. Its complete statement is as follows:

"Cease dependence on inspection to achieve quality. Eliminate the need for massive inspection by building quality into the product in the first place."

The idea that quality should be built into the design of the products and into the processes to manufacture them has come to be generally accepted in the past 30 years, and implemented in many industries. You never hear anyone arguing against it. At the same time, final inspection and test has never completely disappeared, even in the car industry. Engines, for example, are all tested before moving on to assembly, even at the best manufacturers, and body paint is visually inspected by people.

In the details he gives about this point, Deming acknowledges that there are exceptions where no one knows how to build quality into the process. In particular, he mentions integrated circuits. It is still true in 2012, and the economic importance of this "exception" has grown in the past 30 years. There are also other, older technology products for which there is no alternative to sorting the output. Lead shot, for example, is produced by pouring molten lead into a sieve, collecting the solidified drops, sorting the ones that are sufficiently round based on their ability to roll down chutes, and recycling the others.

Oddly, Deming includes "calculations and other paperwork" in a bank among the activities for which mistakes are "inevitable but intolerable." Today, an individual using on-line bill-pay to settle a utility bill expects that the exact amounts will be properly debited and credited without human intervention. If, on the other hand, you are occasionally transferring $300K from Russia to the US, you can expect humans to validate the transaction.

At least in Out of the Crisis, Deming does not distinguish between inspection and testing. Inspection is a manual process, subject to human error and to dilution of responsibility when a product is subject to multiple inspections, which is why he describes it as ineffective as a filter for defectives. At the end of their process, however,  integrated circuits are not inspected by humans but tested on automatic test equipment that, if properly calibrated, provides consistent results. The relevance of these results depends on the human process of programming the test equipment; the productivity of test operations, on the sequencing of the tests.

Because inspection and test is perceived as  "non-value added," it has a bad odor in the Lean community, and is ignored in its literature. Today, however, it is something we have to do, and we might as well do it well. Deming discusses it in Chapter 15 of Out of the Crisis;  I, in Chapter 16 of Lean Assembly .

3 comments on “Deming's Point 3 of 14 - Cease dependence on inspection to achieve quality...

  1. Comment in the IndustryWeek manufacturing network discussion group on LinkedIn:

    This is still the biggest labor constraint and throughput bottlenecks I run across in small manufacturers, generally self-trained with no one on the crew having worked in a sophisticated manufacturing operation so endless inspection, generally visual and manual, by the the owner himself or other high-cost/high demand help for an additional opportunity cost. That need to inspect everything going out the door, often multiple times, and the time spent on that as well as inspection throughput capacity, is a huge small business growth constraint. "Span of Management" studies find most people can't keep track of everything being done (as a comforting fantasy) in an organization with more than 3-10 employees and so most small businesses never grow beyond that, it took me years and Deming to realize it was the quality inspection practices rather than delegation/loss of control that hemmed in so many business owners.

    One shop with a worldwide reputation for quality in an industry where more formal quality controls keep getting screwed up has an inspector for nearly every production worker (didn't believe it until I was counting noses in their company photos as 40+ quality inspectors at a 100 person company stunned me that much.)

    It's one of the advantages of being able to hire cheaply smart diligent women with poor job prospects in their local economy (better color vision, better attention to detail, better fine motor control/manual dexterity, better concentration, and in small towns always the best workers are almost always badly underpaid even by regional standards.

  2. In one of Deming's books thee is a formula that allows you to calculate the relative costs. The answer about inspection is not absolute. There is a correct economic decision to be made about this in every situation. In this way you can separate the culture, mindset, bad habits ets in an organization from the facts. Inspection reduction activities can be driven by the factors in the calculation mentioned above.

  3. Pingback: Forthcoming book: The Deming Legacy | Michel Baudin's Blog

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