Page 226 - The Handbook for Quality Management a Complete Guide to Operational Excellence

212 P r o c e s s C o n t r o l Q u a l i t y A u d i t s 213

audit standards (e.g., the ISO 9000 family) are designed to determine all
four facets of quality.
One purpose of product audit is to estimate the quality being delivered
to customers; thus product audits usually take place after internal inspec-
tions have been completed.
Product audits differ from inspection in the following ways: (1) audits
are broader in scope than inspections, (2) audits provide more depth than
inspections, (3) audits provide information useful for product quality
improvement, and (4) audits offer another level of assurance beyond routine
inspection. Inspection normally focuses on a small number of important
product characteristics. Inspection samples are selected at random in sizes
large enough to produce statistically valid inferences regarding lot quality.
Audits, on the other hand, are concerned with the quality being produced by
the system. Thus, the unit of product is viewed as representing the common
result of the system that produced it. Audit samples are sometimes seem-
ingly quite small, but they serve the purpose of showing a system snapshot.
Audit samples are examined in greater depth than are product sam-
ples; that is, more information is gathered per unit of product. The sample
results are examined from a systems perspective. The examination goes
beyond mere conformance to requirements. Minor discrepancies are noted,
even if they are not serious enough to warrant rejection. A common practice
is to use a weighting scheme to assign “demerits” to each unit of product.
Aesthetics can also be evaluated by the auditor (e.g., paint flaws, scratches,
etc.). Table 10.1 presents an example of a publisher’s audit of a sample of
1000 books of a given title.
These audit scores are presented on histograms and control charts to
determine their distribution and to identify trends. Product audit results are
compared with the marketing requirements (i.e., customer requirements) as
well as the engineering requirements.
Product audits are often conducted in the marketplace itself. By obtain-
ing the product as a customer would, the auditor can examine the impact of
transportation, packaging, handling, storage, and so on. These audits also
provide an opportunity to compare the condition of the product with that
being offered by competitors.

Problem Seriousness Weight Frequency Demerits
Cover bent Major 5 2 10
Page wrinkled Minor 3 5 15
Light print Incidental 1 15 15
Binding failure Major 5 1 5
TOTAL 23 45

Table 10.1 Book Audit Results

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