How do other professions demonstrate competence in interviewing?

All the recent discussion of interviewing practices got me wondering how other professions that require deep skills test the competence of applicants in an interview process? Are doctors required to diagnose something? Do architects have to solve a design problem or interpret a drawing? Or are these steps rendered redundant by things like state boards and licenses? Would like to hear from other professionals who have had to "white board" what they can do in order to get to the next stage of an application process.