Which of the following is NOT an acceptable method of verifying a corrective action?

In the context of verifying a corrective action, the most reliable methods involve objective evidence that can demonstrate the effectiveness of the corrective measures taken. Collecting or observing the new results, such as measuring outcomes after the implementation of corrective actions, provides direct evidence of improvement. Additionally, reviewing measurement records can also substantiate the effectiveness of the correction as it shows quantifiable changes. Conducting another audit offers an independent evaluation of the correction, yielding insights from a systematic examination of processes.

Contacting the individuals responsible for implementing the correction, while informative, relies heavily on subjective interpretations and assurances from those directly involved. It does not provide objective data or evidence to confirm that the corrective action was effective. Therefore, this choice is less suitable as a standalone method for verification, making it the correct answer to the question regarding which method is NOT acceptable for verifying a corrective action.