Contents - Index

Defects Per Quantity

Inspections for defects per quantity count the number of defects that occur in a specified quantity of product.  This quantity is generally a length, area or volume.  However, it could also be a weight, time period or other quantity.  Some units of measure will be associated with the quantity.  The quantity is not restricted to integer values.  For example, 1/2 a cubic yard of cement might be inspected for organic material.

The types and sources of sampling plans for defects per quantity are:
  • Single
  • Double
  • Multiple
     
    Many prefer to use the term nonconformity to clarify that failure to meet a requirement does not necessarily imply that the unit of product is unfit for use.  For example, a requirement may have been set for a particular dimension.  Passing the requirement ensures proper assembly of the parts.  But failure to meet requirements does not imply the parts will not assemble properly.  It only means that proper assembly cannot be guaranteed.