Does C = 0 Sampling Really Save Money?

Only if you count just the cost of the customer’s inspection

The claim is made and widely believed that C = 0 sampling plans are more cost effective than classic sampling plans such as ANSI/ASQ Z1.4. Below is a preliminary analysis of the cost difference between the two sampling plans using the hypergeometric probability distribution to compare a Squeglia C = 0 sampling plan with the ANSI/ASQ Z1.4 Single Normal sampling plan.

However, before starting our investigation we need to define some of the important terms used in acceptance sampling.

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Comments

But what are the system costs?

You make some very good points about looking at the system costs, but it seems to me that if you are considering system costs you need to look at the whole system. For example, what is the cost to the customer of a defective part getting into their process? How about 2% or 4%? And what if it makes it out the door to the end user? Wouldn't these costs be relevant also?

C = 0 vs Z1.4

Beth, The answer to your question is yes these customer costs are certainly important. However, we are comparing two sampling procedures which have essentially the same AQL So the quality of the product accepted by the customer should be very similar. In which case the costs that you are referring to should be approximately the same. So for comparison purposes we can ignore them. Regards, John

Sampling economics and customer protection

Dear sirs:

Can I know what are the major differences of sampling plan metircs (OC curve, AOQ, ATI) among the classic c=0 sampling plan (since 1963), c=0 in ANSI/ASQ Z1.4 2008 and c=0 in MIL-STD 1916 (since 1996)? Thanks a lot.

Tom