Measurable DBA Performance Standards

What is a DBA's worth? There has been discussions on this, but I have not seen anything on evaluating this IT entity. Employees want to know what is expected of them and this should be based upon some measurable standards. These standards should be developed with open discussions between the manager and the employee. I am hoping the TechRepublic's brain-trust would share some of the "measurable" standards they have established for their DBA members.