By far, the most accurate means of telling if an applicant will be successful is to know his IQ. Since that's been forbidden, employers need roundabout methods of telling who's going to be worth hiring.
Cognitive ability testing is not forbidden. In fact it is alive and well. Companies need to demonstrate that it is relevant to the job in question and that it is not unfairly "biased" (i.e., has different predictive validity) for protected groups.
For many jobs, cognitive ability is the best SINGLE predictor of success, but there are many other predictors that neeed to be taken inot account. Thats why companies use multiple interviews, personality tests and organizational psychologists to help them with their hiring.
Not true. Some employers are looking for SPECIFIC personality types for specific jobs.
I've tested WAY above average in IQ tests...but didn't get a job due to a personality test. They were looking for a PURE analytical type for a Project Manager position...and I'm not that.