Tokenadult isn't around to chime in here, so I'll take his place today. Hunter and Schmit did a meta-study of 85 years of research on hiring criteria. [1] There are three attributes you need to select for to identify performing employees in intellectual fields.

  - General mental ability (Are they generally smart)
    Use WAIS or if there are artifacts of GMA(Complex work they've done themselves) available use them as proxies.

  - Work sample test. NOT HAZING! As close as possible to the actual work they'd be doing. Try to make it apples-to-apples comparison across candidates.

  - Integrity. The first two won't matter if the candidate is a sociopath.

This alone will get you > 65% hit rate. [1]

[1] http://mavweb.mnsu.edu/howard/Schmidt%20and%20Hunter%201998%...