Because the cost of a bad hire is so high, some organizations are resorting to a variety of psychometric tests to determine if it's worth interviewing and possibly hiring a candidate. If you, like me, are suspicious of tests, take a look at The Einstein-Clavin Effect by Wendell Williams. My favorite quote:
… controlled research studies confirm the fact that people who “fake good” on self-reported tests can outscore folks who give honest responses. Burn that into memory: People who “fake good” on self-reported tests can outscore folks who give honest responses.
So, if you're using some kind of test (tests are not auditions, which are useful), see if you can correlate any previous hiring with the results on the test. I bet you can't.
Tests don't predict behavior on the job. Behavior-description questions and auditions do. I'd much rather spend the time interviewing well than pay for a test that doesn't predict work behaviors.