What is the least likely method for checking quality control in a repair shop?

Maintaining a log of redeemed coupons each month is the least likely method for checking quality control in a repair shop because it primarily reflects promotional activity rather than service quality. While tracking coupon redemption may provide insight about marketing effectiveness or customer engagement, it does not directly assess the quality of the repairs or services performed.

In contrast, conducting customer satisfaction surveys, performing regular inspections of technician work, and reviewing feedback from service callbacks are all direct methods of evaluating service quality. Customer surveys gather firsthand feedback from clients regarding their experiences, regular inspections ensure that the work performed meets established standards, and analyzing service callbacks helps identify patterns or recurring issues that may indicate quality concerns. These practices focus on ensuring that the shop delivers high-quality service consistently, which is fundamental for maintaining customer satisfaction and trust.