srothstein is dead on about nailing down the definition of response time, especially if you doing analysis or comparisons. If you really want to get a handle on it, ask also for all dropped calls and the reasons they are dropped. Sometimes it is because people hang up on their own, but it can also be that the caller was on hold for so long, he/she got tired of waiting (or couldn't wait) until a dispatcher could handle the call.
A lawsuit in Chicago a couple years ago about responses to fire revealed that there were a huge number of these types of calls -- seemed like it was 20% or more. The lawyer involved put them on his website, and Chicago counter-sued him to remove them, claiming it gave potential terrorists too much info. I have my doubts that was the real reason.
elb