Asking the right questions and listening to the answers can keep your call-backs down and your customers happy.
How do you define a call-back? To me, it's whenever you have to go back to a customer's home and you're not getting paid for whatever reason!
To many of my techs, the definition of a call-back was something they had worked on that didn't fix the problem. If the return visit was for any other reason, they felt it shouldn't count as a call-back. I remember on more than one occasion a customer would call for no heat after we had been there. The tech who went back would call on the radio: “It was just the emergency switch left in the off position.”