Client would like SMAs/Investment Managers with diverse leadership

Firms that have significant black leadership like Grosvner, Fairview, and Stepstone were mentioned at the meeting. What's the best way to research this?

Edit: getting a ton of non-answers here, so let me clarify here - IDGAF what any of you think about the merit of this project & neither does the client.

I need to make an effort to research and CONFIRM that there really is nothing better out there.

We all know what the answer is PROBABLY going to be that diversity = worse returns, but I am not returning to this client, with that conclusion, without at least having some evidence in hand. Some of you are talking about fiduciary duty. Yeah, conducting this research IS my fiduciary duty. The conclusion, backed by hard evidence, is important. ONLY THEN can I steer the client

If anyone has any experience with this, feel free to comment.