The most relevant measure of customer service performance is:

 Customer service performance is the degree to which a product or service meets or exceeds customer expectations. The most relevant measure of customer service performance is how the customer perceives the service compared to what they expected. This measure reflects the customer’s satisfaction and loyalty, which are key factors for business success. Other measures, such as service promised versus measured, customer complaints, or positive feedback, are more related to the supplier’s perspective and may not capture the customer’s true perception of service quality. References : CPIM Part 2 Exam Content Manual, Domain 3: Plan and Manage Demand, Section A: Demand Management, Subsection 4: Customer Service Management, Page 11.