Initially we had the superclass Customer and then the two subclasses payee and patient. For example payee is a customer who only pays the bills and patient are customers who receive treatment/services. However the project description says payee and patient have the same attributes, DOB and Medicare Numbers. Given that there are no differences in the attributes of those entities, is it appropriate to merge them into a single entity? Cheers.

I read the case study again!! It says: "For each actual patient, their Date of Birth (D) and their Medicare number (S 12) are also recorded, along with which customer is currently responsible for paying for their treatment". For the payee that data is not recorded.