One of the critical skills for any recruiter is evaluating a resume to determine if there is a fit. Thus, I feel before any recruiter is hired, it is wise to test a recruiters skill in this area.
One way to do it is to give a job description. Then, show two sample resume and then have the recruiter state which resume is the best fit and why.
Another way to do it is to show a job description and then show a resume. Then ask the recruiter if they would would interview the candidate. A) Yes B) No C) Maybe. Then justify their answer.
A recruier has to demonstrate that basic skill.