Many employers like to use IQ test scores as an indicator of how well an individual will do for the job they've applied for. Is this right or wrong? I think that though IQ testing can be a useful tool for selecting a new worker, it should not take priority over other methods to predict quality job performance.
IQ testing, at first glance, seems like a very good way to decide on who to give a job. There's a slightly positive correlation between IQ score and job performance.
Though there is a positive correlation between IQ score and job performance that doesn't mean that it's a perfect correlation. For all the people that have a higher IQ than someone else and does better at a job because of it, there are some with lower IQ's that would have done a better job. It's similar to those who know how to look themselves good in interviews versus those who get too nervous to do so--just because some people get nervous for them doesn't mean that they wouldn't be good at their job, the same as the person who knows how to make themselves look good wouldn't necessarily do a good job.
IQ scores should be used as one of many methods of predicting job performance. IQ score isn't perfect at predicting a future worker's performance, which is why that error must be balanced out with other methods of prediction.