$1)$ A quality breakdown structure $($QBS$)$ is similar to a work breakdown structure $($WBS$).$ Its primary function is to break down the organisation and production systems into individual components or packages to such a level that:

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a$)$ the various quality managers and controllers can be assessed for effectiveness.

b$)$ each component or package can be individually controlled to an adequate level.

c$)$ the quality policy can be correctly and accurately developed.

d$)$ operational cost limits can be applied.