Most of us think that IQ and work place performance are related. There are not directly correlated.
There is also no clear relationship between performance at school (grade point average) and performance on the job.
People with high levels of work place cognitive ability – the ability to problem solve and to be creative in relevant work place contexts can perform at higher than average levels. But they mak not so so. Performance on the job is the complex interaction of many factors. A number of them have to do with the work culture of the organization, and the capasbility of the person’s boss, rather than the candidate’s level of cognitive ability.
Howver, having insight into a candidate’s level of work related cognitive ability does help a recruiter make useful predictions about a person’s potential performance in a role.