I have to built a customer churn model for of a teleco. The churn rate is 15 %. There is no particular campaign conducted. By churn I mean customer leaving the teleco permanently.
Data is available from Jan 2012 to Dec 2014
- Should i have a fixed performance window? i.e. i will only flag customers who churned from July 2014 to Dec 2014 as churners & use only data from before July 2014 to create predictors in the model.
- I will consider customers who churned from July 2014 to Dec 2014 only but performance window will be rolling. Example if a customer churned in nov 2014 i will create predictors using data before nov 2014. If a customer churned in sept 2014 i will create predictors using data before sept 2014.
Which is the best approach, using fixed performance window or rolling performance window? What is the pros & cons of these 2 approaches?