ABSTRACT
This chapter discusses the decisions that may be made as a result of inspections for materials evaluation and nondestructive testing. These include the selection of a threshold level for acceptance/rejection of parts, the concept of false accepts and false rejects, and how these vary with the chosen threshold. The quantitative comparison of the effectiveness of different inspection procedures can be made using the relative operating characteristics curve. Finally, the idea of using materials evaluation or NDT for lifetime extension is discussed, where it is seen that the use of such inspections can lead to economic benefits, such as lower running costs due to less frequent replacement of parts, or timely replacement of parts, thereby avoiding costly failures.
