I would like to pose a question about how to treat additional holders in the propensity-to-buy models of banking products.
Up to now I was only taking into considerations the clients as first holders. For example, if a client ‘1’ appears as the first holder of a saving account ‘A’ with a balance at the end of the month of 100€ and as an additional holder of a saving account ‘B’ with a balance at the end of the month of 50€, the saving balance at the end of the month for the client is considered to be just 100€. Moreover, if a client only appears as an additional holder (and he/she is not a first account holder of ANY product), he/she is dismissed by the model.
However I have been told to include additional holders in the models (additional holders have the same rights of the first holders).
One possibility is to recalculate all the variables summing up the position as first and additional holder (in the previous example, the balance at the end of the month of client ‘1’ would be 150€). Together with this, I would create some variable that represents the maximum degree of intervention of the client in the account (ex. 'first holder', 'second holder').
Another possibility would be to “double” all the variables, considering the client as first and additional holder (in the example, we would create two variables: the balance at the end of the month as FH =100€, : the balance at the end of the month as AH =50€).
Did any of you encounter a similar problem?It would be very helpful to understand how you solved it.