Customer service agents are critical to keeping customers happy, managing customer accounts and technical problems, and up-selling the client to new services. There are a few important metrics that can be set-up in a pay for performance system.
The easiest metric is new sales or up-sales. The agent should be granted a commission on the new revenue that they initiate.
Response time or call time are other important factors as well as the difference in response time versus other agents.
Customer feedback is the last important factor. Customers should be provided surveys asking whether their issue was resolved and was the agent helpful or considerate. These answers provide measurements that can be used for performance metrics.