There are several levels to define churn, namely Customer, Account, and subscription. For some operators with only limited business line, customer and account churn at same time, while subscription is at a lower level. Customer can stop using some products (termination of subscription) while continue to use the other products. In later case, operator still has the customer and may promote other products in the future. However, if customer completely stopped using any products from the operator, it is very difficult for operator to bring customer back.
In Oracle Communications Data Model, the churn was defined at Customer Level, which is, a customer is recognized as a churner only when he stop using any product from the operator.
If customers churn at a given month, the model may receive the data only three months after the actual Churn. In this case the time window should be adjusted.