What is a sign that a procedure is effective and does not need revision?

The correct choice highlights that a rise in customer praise is a strong indicator that a procedure is effective and does not need revision. When customers express satisfaction and show appreciation for the service or product, it suggests that the existing protocols are meeting their needs and expectations. This positive feedback confirms that the procedure is functioning effectively, demonstrating that customer perceptions and experiences align with the desired outcomes.

On the other hand, while a change in relevant problems, a shift in demographics, and an improvement in crew performance may provide useful insights, they do not directly correlate with the effectiveness of a procedure from the customer's perspective. A change in relevant problems might indicate new issues arising that require attention, a shift in demographics may necessitate adjustments to target different groups, and an improvement in crew performance, although important, does not by itself guarantee that customer satisfaction has also improved. Therefore, customer feedback, represented by the rise in customer praise, serves as the most reliable measure of a procedure's ongoing effectiveness.