are other forms of behavioral segmentation that can yield even more and better information about customers. Revenue numbers only give us clues about how customers use our services. Looking at how they actually use the phone on a day-by-day, call-by-call, minute-by-minute basis can provide much better insights. The way people use our telecommunications service is called utilization behavior. Getting Utilization Data - from Billing or Call-Detail Records Of course, getting our hands on utilization information takes a little more effort than uncovering their buying behavior. Collecting utilization behavior is a big job because customers make millions of calls per day, and the only way to map their utilization behavior is to sort through all of those records and pull out what is of interest to us. There are two levels of utilization behavior that we can take a look Chapter 11 Reviewing Billing System Records At the higher level we have the utilization analysis of billing system records. Since most billing systems provide customers with a complete list of every call made, it is easy for us to discover all kinds of interesting information about the caller's behavior from those billing transactions. Some of the more popular forms of call record analysis, developed by Dr. Paulo Costa, the world's leading authority on telecommunications segmentation analysis, include the following. Duration of Call Analysis - Categorizing the number of calls placed by the number of minutes they last (e.g. 10 calls between 1 and 5 minutes, 25 calls between 5 and 10 minutes) From-To Analysis - Attempting to identify patterns in the places that a person calls (For example, does the person call the same three numbers repeatedly or different num- bers every time?) Time-of-Day Analysis - Looking at the time periods with- in which most calls are made Hybrids - Hybrid analyses that look at unique combina- tions of the first three approaches such as patterns between time-of-day, from-to and duration (For example, some make long phone calls during 