to mean 1 minus the churn rate. For example, for a group of subscribers, an annual churn rate of 25 percent is the same as an annual survival rate of 75 percent. Both imply a customer lifetime of four years. I.e., a customer lifetime can be calculated as the inverse of that customer's predicted churn rate. For a group or segment of customers, their customer life (or tenure) is the inverse of their aggregate churn rate. Gompertz distribution models of distribution of customer life times can therefore also predict a distribution of churn rates. For companies with a fast-growing customer base (e.g., digital media companies in a BCG-matrix problem child or star phase), confusion can arise between the statistical analyses associated with what percentage of the whole customer base churns in a given yearWhat percentage of the base of subscribers in all of 2010 churned out?versus a particular customer cohort's churn rate. For example: Taking those customers who subscribed in given month, say January 2010How many had churned out by January 2011? Examining churn for a fast-growing aggregated customer base will understate the true churn rate compared to cohort based approach to the calculation. The cohort based approach will also allow you to calculate the survival rate and the average customer life, whereas the aggregate approach can not calculate these two metrics. Researchers at Deloitte have argued that social network analysis is a good tool to calculate churn. In recent years, using AI and machine-learning as a means to calculate customer churn has become increasingly common for large retailers and service providers. The phrase "rotational churn" is used to describe the phenomenon where a customer churns and immediately rejoins. This is common in prepaid mobile phone services, where existing customers may take up a new subscription from their current provider in order to avail of special offers only available to new customers. In most circumstances churn is seen as indicating that customers are dissatisfied with a service. However, in some industries whose services delivers on a promise, churn is considered as a positive signal, such as the health care services, weight loss services and online dating platforms. Some researchers have disputed the simple assumption that just dissatisfaction would lead customers to churn, and called for a more nuanced approach. See also Turnover (employment) Customer attrition Customer retention Turnover References Further reading Cached Insight paper on churn in the mobile communications