Assessments work.  Broad-spectrum assessments work best.

Key findings from 85 Years of Research into Organizational Psychology.  General mental ability combined with a work sample, and a structured interview that assesses integrity and conscientiousness, is among the very best processes in the historical literature.  Summary reproduced below:

This article summarizes the practical and theoretical implications of 85 years of research in personnel
selection. On the basis of meta-analytic findings, this article presents the validity of 19 selection
procedures for predicting job performance and training performance and the validity of paired
combinations of general mental ability (GMA) and Ihe 18 other selection procedures. Overall, the
3 combinations with the highest multivariate validity and utility for job performance were GMA
plus a work sample test (mean validity of .63), GMA plus an integrity test (mean validity of .65),
and GMA plus a structured interview (mean validity of .63). A further advantage of the latter 2
combinations is that they can be used for both entry level selection and selection of experienced
employees. The practical utility implications of these summary findings are substantial. The implications
of these research findings for the development of theories of job performance are discussed.

Key table summarizing results included.

Full study here:

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