Why not base your decision on the candidate's academic qualifications?
College and university exams are far more rigorous and comprehensive than any interview tests can ever be.
LOL!
Degrees are not a sign of competence. There are many folks with CS degrees that can't problem solve and many MBAs that can't manage. The best programmer I know is self trained, the second best was a music major. The best DBA I've been around has a culinary background. (He's also a MCM, too.)
Steve mentioned self publication. There's a large number of people attempting to "game" that too. There's a lot of blog postings out there that are cribbed 99 percent from other reputable sites and MSDN articles.
If an employer or potential employee really wants to test capabilities two things come to mind. Have a true professional screen the applicant. A top level DBA can figure out the level of an applicant with 3 questions and in about 20 minutes. Also a company can test the applicant on site before hiring. Toss them in front of a VM with SSMS up and see what they can do.