Seven Basic Quality tools documents
Definition of Quality Management -- it is a method for ensuring that all the activities necessary to design, develop and implement a product or service are effective and efficient with respect to the system and its performance. It is also a principle set by the company to endure the continuous advocacy of quality services and products, or the further improvement of it.
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Consumer and Producer Risk
Original text
on www.freequality.org
In this brief tutorial, I will explain the concepts known as consumer and producer risk. I will establish the basic concepts of acceptance sampling and other concepts necessary to understanding consumer and producer risk such as acceptance sampling techniques, the various measures, and applications.
I
will first provide a general definition of these two types of risks and by
elaborating on acceptance sampling later, their true significance will become
more apparent. Producer risk is most
simply described as the risk associated that after performing an acceptance
sample on a lot, a producer determines that a lot has an unacceptable number of
defects and the lot must be subjected to complete inspection. When, in reality, the sample has a larger
percentage of defects than the actual lot does. Consumer risk is the risk associated as a
consumer of a product, that after performing acceptance sampling, you determine
that the lot has an acceptable number of defects, but, in
reality, the lot has a percentage of defects above the acceptable level, more
than the sample you took does.
Acceptance
sampling is frequently used as a method of reactive quality assurance, it
eliminates the time and labor associated with performing 100% inspections on
lots of products that are produced or received.
Acceptance sampling is often used where the cost of missing a defective
product is relatively low, large lots are present and inspectors become
complacent, there is a fast production rate, or inspection demands destructive
inspection. 1 By using statistical
techniques, firms can determine what sample size and acceptable defect
percentage they will apply to their sampling techniques to minimize the risk of
consumer and producer risk. Acceptance
sampling is a particularly cost effective means of controlling quality when you
start producing new products of institute new processes, when you restart a
production line, when you deal with fragile products, when dealing with a new supplier, or
when dealing with perishable products.2
There are several important terms associate
with acceptance sampling and limiting the possibility for consumer and
producer’s risk. The normal distribution
is a basic statistical principle, which describes how most samples when charted
against the number of standard deviations of the characteristic of interest
from the mean value, the most fall closest to the mean and decrease
symmetrically in a bell shape. This is a
basic explanation of how the distributions should fall in most samples. In general if a sample deviates too much from
this shape, there appears to be some anomaly in the production or shipping that
mutates the symmetry of the bell shape.
Furthermore we can set a maximum number of standard deviations from the
mean and if an unacceptable number of items fall outside these limits, this
means there is an excessive risk that the lot exceeds quality standards. OC Curves ( Operating
Characteristic Curves) estimate the likelihood that a lot will be accepted by
the customer given your quality sampling calculations. 2 Acceptable Quality Level (ACQ) is the
largest number of defective products in a lot that is still acceptable. 2
Many
companies go to great lengths to encourage these and other techniques use both
by themselves and their suppliers. For
instance, Pacific Bell trains its management in these techniques and offers
free training to it’s suppliers as well as offering a reward program to these
suppliers for outstanding quality levels.
Consumer and producer risk are just two elements of the many sampling measures for insuring quality that are becoming ever more recognized in firms. For more information,