HR departments are not being very smart about intelligence testing. Apparently, the use of intelligence testing in hiring and promotion is increasing without much thought to accuracy. The latest issue of HR Magazine has an article by Martha J. Frase in which she writes, “Evidence is accumulating that mental ability is the best way to measure predicted job performance.” This trend troubles me because organizations run the risk of hiring the wrong people, missing the right people, and alienating everyone. I have no doubt that for many jobs there is a strong relationship between mental ability and job performance. The question is, “Do we have a useful way of measuring the kinds of mental abilities that affect performance on a particular job?” The answer is, “No.” The most commonly used and rigorously developed intelligence tests are, from a psychometric and statistical standpoint, valid and reliable. But from a practical, workplace standpoint they are lousy predictors of performance. At best, a test score accounts for less than a third of the variation in any performance score. A standard intelligence test might be the best single predictor of performance, but other factors explain more of an individual’s performance than do intelligence tests. Other individual characteristics such as previous job performance, attitude, interpersonal skills, aspects of personality, etc., are probably of equal or greater importance.

We also have to ask,”What do we mean by intelligence?” There are many intelligences so one has to decide which ones to measure. The APA 1996 Intelligence Task Force Report says:

It is widely agreed that standardized tests do not sample all forms of intelligence. Obvious examples include creativity, wisdom, practical sense and social sensitivity; there are surely others. Despite the importance of these abilities we know very little about them: how they develop, what factors influence that development, how they are related to more traditional measures.

Something else that makes me nervous about the use of intelligence tests is that many examiners do not have adequate skill to administer, interpret, and explain the results to the person being tested. To do this well requires a high level of psychometric and counseling ability. The scores need to be understood in context and along with other information about the employee’s performance and the scores should be interpreted and explained to the employee and others in a manner that is appropriately respectful of the well-being of the individual. Also, there are ethical issues related to confidentiality and long-term record keeping that have not been adequately resolved.

Testing is popular because it appears scientific, it is much easier to use than the other indicators that are available, and at this point we do not have a better single measure. We would like to believe that an intelligence test score can make the hiring and promotion decision for us. But the truth is that it’s not adequate. I believe the best indicator of future job performance is still a combination of past job performance and attitude toward the specific job and co-workers. This is harder to gauge but worth the effort.