[ScottBurson]

The argument for technical people is not that a more diverse group per se produces better results (although that argument is made for some other professions, such as marketing). The argument is rather that by restricting the candidate pool based on irrelevant attributes like ethnicity or gender, one is likely to overlook good candidates and thereby reduce the overall competence of the team.

I would expect you to agree with this since you say you haven't observed a systematic difference in performance between these groups. No?

My own thinking is that it's good to invite a diverse applicant pool, but final hiring decisions shouldn't use diversity except as a tie-breaker. At the same time one should try to be aware of one's own biases, and rigorously careful not to devalue candidates unlike oneself.