Good employee performance metrics to keep track of?

Hi all. We want to start keeping more objective measurements of employee performance, both for our records and for DE&I. (Need to make sure managers are evaluating all employees on the same criteria so there’s no room for unconscious bias to creep in.)

Super excited about this initiative, but not sure where to start. What are the most effective performance metrics that you track at your organization? What kind of scale fo you use?