Deming: “Cease Dependence on Inspection”

[From the Archive: Originally posted at Amplify.com Jun 29, 2009]

Deming’s view on inspections, which I share: “Cease Dependence on Inspection”.
(Caveat: He way talking about manufacturing and factory lines. Collaborative knowledge work, such as product design or software development, is a different context which will require some re-interpretation and repurposing of the fundamental concepts underpinning his words).

I also recognise that many folks may feel so uneasy in some extreme situations – for example, where life and limb are at risk – that they may still choose to require inspections (via statistical sampling, or even 100% inspection).

Aside: I’d suggest that such unease generally comes from a lack of trust in the effectiveness of the process(es) involved.

Amplify’d from curiouscat.com

From Deming’s 14 management points: “Cease dependence on inspection to achieve quality. Eliminate the need for inspection on a mass basis by building quality into the product in the first place.” Out of the Crisis, 1982.
Prior to Deming’s ideas being adopted inspection was often used to select out the bad products. Companies would make products then sift through the resulting output removing those that were defective. If they could re-work them to be sold they would do so. Otherwise they would scrap the defective output.
Obviously this is a costly way to do business. It is much better to work on improving your processes so the output is all acceptable. Deming used to colorfully describe the old practice as “you burn the toast, I’ll scrape.”
Deming believed in improving the process, and doing so using process measures to guide improvement efforts.

In the New Economics, page 179, Deming states:

Conformance to specifications may be achieved in several ways:

1. By careful inspection, sorting the bad from the good. Dependence on inspection is hazardous and costly.
2. By work on the production process to shrink variation about the nominal value.

Obviously, option two is the preferred method. He also recognized that there are extreme situations where 100% inspection may be required (where safety may be jeopardized for example).

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