Customer lifetime value (CLV), a forward-looking indicator of customer profitability, became common parlance as relationship marketing gained momentum. However, calculating CLV remains a significant iterative process within organizations and is often fraught with challenges in each step. At best, organizations arrive at close estimates based on how they choose to design the model. But the process remains expensive, error-prone, and often lacks real-world application. The effort required to prepare for and progress through model development is where customer intelligence (CI) professionals need to do the heavy lifting. To help, Forrester recommends a three-phased approach to determine lifetime value.