I take the point but by their own admission, resume acceptance is at 50% when it could be at 80% so on that score they are failing to convince the client of the benefit of that diversity.
If I am a hiring manager and I am rejecting 1/2 resumes as opposed to 1/4, I'd question what the search firm is doing.
If I am a hiring manager and I am rejecting 1/2 resumes as opposed to 1/4, I'd question what the search firm is doing.