Sorry, I think I posted a less succinct version of your response. ;-) Seems to me I'd want every available attribute to be available for every type of employee. It might make more sense to use a comprehensive baseclass rather than interfaces even. I'm assuming that the customer themselves would want control over it, meaning the attributes might benefit from being split out into table/array/XML datastore/whatever with a UI allowing the customer to edit the attributes. If it's done with a table or XML I'm told there is a wonderful new concept called "SQL" that uses "joins" to make this sort of thing easier than ever. ;-)