An economic analysis of inspection costs for mistake-proofing binomial attributes

Mistake-proofing (or poka-yoke) devices are used to insure that conditions for high quality production exist (source inspection) or to provide rapid f eedback on defects (self-checks). In this paper, self-checks are shown to b e a special case of the np-control chart, not a competing process control m ethod. Existing economic control chart design models are employed to show t hat managerial actions cannot always make self-checks as cost effective as other np-chart designs. A model of source inspection is analyzed to determi ne how low inspection costs must be in order for source inspection to be ec onomical.