ways. Although we cannot tell you exactly what should go into a base segmentation, we can provide some guidelines for their construction. There are two types of base segmentation; one defines consumers, the other businesses. (Small and medium business segmentation schemes are a hybrid of the two.) Consumer Base Segmentation Consumer base segments pull segmentation criteria from all three of the major segmentation categories (behavior, demographic, geo- graphic). However, some criteria will be more useful than others eXcellence in Telecommunications The Telco Churn Handbook will. Behavioral Segmentation Basis By far the most useful factor for developing a base segmentation is behavior. Behavioral criteria are and should be the primary basis of telecommunications segmentation because it is the customer's telecommunications behavior that is the most important to the firm. Demographic and psychographic information might be useful, especially when targeting of specific campaigns. However, what is most important to the telco is not the consumers' age, sex, or income but how much they use their telephones. Many wireless companies have intuitively gravitated in this direction for many years now. They use a Gold/Silver/Platinum classification system that ranks customers by their monthly revenues. Customers with very high monthly bills are placed in the Platinum category; the next highest group is Gold, and SO on. This base segmentation scheme guarantees that anyone dealing with that particular customer will know how valuable this consumer is to the firm. Average customer revenue, average usage in minutes, the numbers and types of additional products used, and the trend in usage are some of the behavioral component of the base segmentation. Demographic and Psychographic Enhancement To be truly useful, a base segmentation needs additional information about the customers. Once distinctive behavioral groups of customers have been identified, it is often useful to conduct more detailed demographic and psychographic research. A