Establishing a permanent global employee id

Greetings,

Let me preface this by saying that I am new to SAP, new to HCM, and new to the forums. Apologies if I do not have all the terminology down quite yet.

We are getting ready to kick off our HCM implementation with deployment of OA and PA. We will be relying on consultants for the technical work.

One benefit that we hope to derive is that we can create an employee ID number for each employee that stays with them for their career. This would essentially become a primary identification key that we share with other systems and partners. Thus, no matter where you go, you identify yourself by your WWID (World Wide ID #). This number should never change, just as your SSN never changes.

I have learned that the way SAP HCM works is that each time an employee moves to a different entity (company code, overseas assignment, etc.) his personnell number changes. That seems odd to me but it is what it is.

Given that the personell id could change, what would be the best approach to creating and maintaing the permanent id number?

Many thanks,

Mike