a- tion) Behavioral (organizing customers by behavioral character- istics - including, most importantly, their buying, shopping, and product usage behaviors) Demographics and Psychographics (organizing customers by their physical, social, psychological, or attitudinal char- acteristics) Each of these major categories of segmentation contains hundreds of variations and levels. More importantly, real, practical segmentation schemes are typically hybrids of combinations of sometimes dozens of characteristics from each of these three major categories. Segmentation Membership Issues We also saw that, when it comes to building segmentation schemes, several issues arise about the mechanics of organizing the segmentation schemes. Included are issues regarding: Exclusivity - Should the segments be organized SO that membership is mutually exclusive (each customer belongs eXcellence in Telecommunications The Telco Churn Handbook to one and only one segment?), or should a customer be al- lowed to belong to several segments concurrently? Inclusiveness - Should the segmentation scheme be built SO that all customers or prospects are forced to participate in at least one segment, or should the scheme only classify customers that meet the appropriate criteria? Hierarchies - Should hierarchies of segments be built, or should it be a simple, one-dimensional structure? Recombinant VS. Disassociated Membership - Can the members of one segmentation model can be cross-checked against membership in other models? Transient VS. Stagnant VS. Renewable Models - What is the lifecycle of the model and how will it be refreshed when required? Segmentation Applications We also saw that different segmentation approaches can be used to accomplish different goals, including: Identification of clusters of customers with similar wants and needs Organization of groups of customers for management pur- poses Development of targets for specific treatments (campaigns, programs, and policies) Creation of measurable units for tracking the success of custome