requirements. The source of a defect is an error. However,
the errors may or may not lead to defects. Such defects are
nonconformities to stated requirements or to human
expectations. Defects may or may not lead to failure when
meeting the required specifications, as a defective item may
pass all quality inspections and tests. This is evidence of the
fact that not every error leads to a defect and not every
defect results in a failure. Also, a failure may arise from a
combination of defects