The Limited recognizes sales associates who provide excellent customer service by rewarding them with a "Hero Award", which is displayed in the store where the sales associate is employed. To measure a sales associate's service performance, which type of research should The Limited use?

Lost customer research.

Explanation:

Lost Customer Research: - It is the process of analyzing, gathering and interpreting the root causes to why the group of customer or an individual customer has canceled their service using the company's product.

This research can improve the company's understanding of it's target customers and their position in the market and can also identify the service, product and performance issues and gaps.