I'd like to see some examples of what everyone thinks are the best way to track a sourcers performance and/or progress.  Imagine you had this great idea to hire a sourcer or institute a sourcing team for the very first time in a corporate HR dept. Now imagine you have to justify this existence to upper management on a regular basis...what are the clearest and most concise ways to measure this function?

Please, there's no wrong answer.  Thanks!