The Trouble with IQ

I’ve just spoken to a friend who tells me that the tech company he works for, one of the world’s most well-known brand names, uses IQ or its surrogates – SAT, GMAT, GPA scores and the like – as critical requirement for employment – even if they were scores from many years ago. Basically, they are trying to ensure that their employees are the smartest people around.

But are the smartest the best in any given job? Not necessarily. Take two friends of mine. One, the most successful kid in my high school class, ended up as a CEO in the cable industry and retired after selling his company. He had been a B- student. The other, a kid I knew in my class at Amherst College, had perfect scores on his SATs – two 800s, and top numbers on three advanced placement tests. He now works for himself helping people set up their home computer systems.

If IQ predicted achievement in the working world, you’d expect the reverse career outcomes for my two friends. And that’s the problem: IQ is a mirage when it comes to how someone actually will perform on any given job. It tells you nothing about that person’s drive or self-mastery, their ability to collaborate or empathize, let alone their ethics.

IQ tests predict best how well people do taking similar tests-–i.e, school performance. IQ also predicts well what kind of job a person can get and hold – that is, it roughly reflects a person’s level of cognitive capacity, whether that allows them to be a sales clerk or an astrophysicist.

But once a person is in a job, other abilities matter more than how well they do at taking tests. This is why hundreds of studies have found that IQ predicts job performance best (though not all that well) at the start of a person’s career, and progressively weakens over the course of that career.

Here’s a summary of data on the trivial value of IQ as a predictor of job performance, a dirty little secret that has been well-known within psychology for decades (Ericsson et al, 1993):

The relation of IQ to exceptional performance is rather weak in many domains…For scientists, engineers, and medical doctors…the correlations between ability measures and occupational success are only around 0.2, accounting for only 4% of the variance (Baird, 1985). More generally, prediction of occupational success from psychometric tests has not been very successful. In a review of more than one hundred studies, Ghiselli (1966) found the average correlation between success-on-the-job measurements and aptitude-test scores to be 0.19. Aptitude tests can predict performance immediately after training with an average correlation of 0.3, but the correlation between performance after training and final performance on the job is only about 0.2 (Ghiselli, 1966). Reviews of subsequent research have reported very similar correlation estimates. When corrections were made for the restriction of range of these samples and for unreliability of performance measures, Hunter and Hunter (1984) found that only cognitive ability emerged as a useful predictor with an average adjusted correlation of 0.5 with early job performance. However, a recent review (Hulin, Henry and Noon, 1990) has shown that with increased experience on the job the predictive validities of ability tests for performance decrease over time by an average correlation of 0.6. This implies that ability tests can predict early performance on a job, whereas final performance is poorly predicted.

So what predicts how well someone will actually do? Measures of the specific competencies that distinguish star performers from average in a given job from the average.

“Competency modeling,” as the method for identifying such competencies for a given job is called, has been used for decades by most world-class companies to identify the abilities that foster outstanding performance. That method, detailed in Spencer and Spencer (1993), tells us, for example, that for the tech sector generally, the top six competencies that most powerfully predict star performance are:

  1. The drive to continually improve performance. These people measure how well they do, search for ways to improve outcomes, set challenging goals, and innovate.
  2. They are impactful: they can make persuasive arguments based on hard fact, they know how to tailor a presentation to their audience, and they are concerned about their own or their organization’s reputation.
  3. Conceptual thinking: they identify underlying problems and address them, they recognize the key actions that will make a difference, and they spot patterns that matter and make essential connections.
  4. Analysis: They anticipate obstacles, break problems down systematically, see consequences and implications within a system, and draw logical conclusions.
  5. Initiative: they are persistent in tackling problems, and take on a challenge or solve a problem on their own before being asked to do so.
  6. Self-confident: they trust their judgment, seek out challenges, and operate best when given independence.

IQ itself is not on this list. And an IQ or SAT score may tell you little about the specific cognitive abilities that matter for effectiveness on this list.

To be sure, a high level of cognitive talent is no doubt a threshold ability for entry into the tech sector – though not necessarily for every job: excellence in managerial and leadership positions, for example, depends most heavily on emotional intelligence abilities.

Threshold competencies like IQ are those everyone needs to get and hold a given job. However, smart hiring and promoting looks beyond these for distinguishing competencies, the abilities that identify outstanding performers.


  • L. L. Baird (1985), “Do grades and tests poredict adult achievement?” Research in Higher Education, 23, 3-85.
  • K. A. Ericsson (1993), “The role of deliberate practice in the acquisition of expert performance,” Psychological Review, 3, 363-406.
  • E. Ghiselli (1966), The Validity of Occupational Aptitude Tests. New York: Wiley.
  • C. L. Hulin et al. (1990), “Adding a dimension: Time as a factoring the generalizability of predictive relationships,” Psychological Bulletin, 107, 328-340.
  • L. Spencer and S. Spencer (1993), Competence at Work, New York: Wiley.

11 thoughts on “The Trouble with IQ

  1. restriction of range? in the nba there is little correlation between height and how good you are, but that is only because everybody is already really tall vis-a-vis the general population, the range is restricted. likewise with IQ and job success, both guys are intelligent, and both are in cognitively demanding occupations. The fact that one did much better than the other does not undermine IQ, as the differences only exist within the high-IQ range. It would make more sense to compare a high-IQ individual and a low-IQ individual performing the same job, and there you see that IQ really matters.

  2. It’s interesting to see the correlation between IQ and job performance. However, I think that it is mistaken to equate “excellent job performance” with “success.” Being successful in one’s life is not necessarily about making lots of money or doing one’s day job well. Success can be measured by how well one is able to fulfill their life goals. Who is to say that setting up computers for people is not a satisfying and fulfilling life, even if it doesn’t pay very much? Many successful artists were poor their entire life.

  3. Adrian makes a good point. This discussion is pointless without defining the range. Let’s get real, a mentally retarded person is going to have a lot harder time “succeeding” in life (i.e. finding a well-paying job and creating wealth) than some guy with genius level IQ. Actually, I find it common sense that the higher the IQ, the higher the probability of success, because it lowers the effort required. Tell two people a surefire way of getting rich, and I will bet on the guy with the higher IQ (IF he also has a decent level of “emotional intelligence,” especially discipline and confidence). High IQ just means you have the tools necessary to do the job, but IQ is worthless without EQ, and to some extent, the opposite is true. There are plenty of “nerds” who can solve complex equations but can’t get a date, can’t get a promotion, etc. On the other hand, there are those who are less than bright who try their hearts out and never make it. Incidentally, I read once that somewhere around 128 is the “optimal” IQ, where most millionaires are found. But this study ignored the obvious fact that, as one would note from the bell curve, ~128 IQ individuals outnumber higher IQ individuals many times over. So one cannot conclude that there is a smaller proportion of higher IQ individuals succeeding, and the idea that higher IQ is a hindrance is obsurd. However, as many smart successful people will tell you, I do think there is a point where there importance of IQ starts to dwindle quickly. The law of diminishing returns must eventually kick in. After all, even if some higher paying jobs are very intellectually demanding at first, it seems like most people would be on an even playing field once they have have traversed the difficult learning curve. Of course, it depends on the job, but I’d say this is especially true in the business world. By the way, George W. Bush is hardly a good example of someone overcoming the obstacle of average IQ. I think to qualify for such praise, one would have to NOT have a rich guy, who happened to be the President, for a dad. There are very few examples of average people (and not born rich or to parents already leaders in their given field) who made it to the VERY top in any given field. Gates isn’t one, Buffett isn’t one, Bush isn’t, Trump definitely isn’t, etc. This is not to be used as an excuse, but this is how it is. Just my thoughts.

  4. Perhaps we could we say that intelligence is the engine: the raw force which determines the maximum performance of which the machine is capable.

    But one still has to steer…

    ..and it’s much harder to drive a very high performance car. Gifted individuals face unique challenges. They don’t fit in. Can people develop normally without the company of their peers?

    Perhaps this is a factor which actively works against success in later life. Perhaps the stereotype “geeks” and “nerds” aren’t displaying inherent character traits but the effects of social deprivation.

  5. I was a catholic seminarian for three years. And as far as I know, not only the seminary there where I studied, but catholic seminaries all around the world gives preference to the smartest (academically), this results in weaknesses in other aspects long neglected. That is why most priest,or seminarians may be smart but only few are truly holy(or with integrity),. Because sexual or/and other non-academic skills are swept under the rug in the name of machine-like efficiency in academics. But things are slowly changing in our seminary as I heard recently, the psychology of each seminarian is also worked out , meaning, the other aspects of balanced living (like sex, and interpersonal skills etc..) are being considered not just pure academic intelligence alone. I understand priests needed to have above average intellectual skill to be able to combat various heresies, and also to be able to be a true and acceptable teacher of the people under their care. BUT IT IS NOT ENOUGH,as Gardner’s and Goleman’s and the likes studied: WE ALSO NEED PRIEST WHO ARE ALSO SKILLED IN OTHER AREAS OF LIVING-like SOCIAL SKILLS and personal skills. Let us pray not just for priests, but also for other non-religious and maybe atheists BUT WITH HONESTY ENOUGH TO MAKE A CONTRIBUTION TO OUR MULTI-INTELLIGENCES.

  6. We are always a product of our genes and our environment.
    I like Noel Darlow’s suggestion that “nerds” may be suffering from social deprivation and wish to comment.

    Both of my daughters are very intelligent but the school system did not challenge them. They were always uncomfortable around most of the other students because of being teased for being “smart”. (God forbid, if you were smart and overweight.) They also did not play sports which didn’t help because of the great importance put on the sports by the entire community.

    My oldest daughter qualified to attend “Governor’s School ” and loved it because she discovered others like her. Unfortunately, it only lasted 8 weeks.

    She is studying to be a nurse so she can help people but lives alone with her two cats and prefers the company of those older than herself.

    Social deprivation is definitely found in USA schools.

  7. IQ and EQ are best in balance. Like most things in life too much of anything isn’t good.

    I have been in executive search for 27 years placing very senior level executives. What I find is a shift from IQ to EQ as one advances up the corporate ladder. In one’s early career IQ is dominant. As one advances and the technical knowledge of the position become less and less a part of the daily job and such things as leadership, motivation of others and ability to drive a team often in conflict to the goal are more important than raw intelligences. Not too say it doesn’t help, but EQ is more important at this level. I have also found the smaller the company the more the CEO’s EQ plays in the success of the company. I believe this is because someone with a strong EQ can get more out of a smaller number of people than someone who has a high IQ, but lacks EQ.

    I find that most senior execs have enough IQ to get them to the level of senior exec, but not all have the EQ to not only sustain success at this level, but to bring together a cohesive team to bring about success.

  8. My parents are of better than average intelligence, but nowhere near being exceptionally bright. This likely accounts for their unabashed pride in producing a child with a “peerless” IQ. I often argue with myself whether it is worth it. I went to college and law school for free, but never went to a class, never had a friend to talk to, and, despite reaching out to professors for friendship, couldn’t find anyone with whom I relate. I am told constantly that I should be grateful that I can do anything my heart desires. Meanwhile, no one wants to hire me, I have no “networking” skills, and the common reaction at my interviews is a contemptuous chuckle. I can assure you there is no “job” that requires a genius intellect, and no one wants to hear how easy school was for you. It is more likely the crutch you fall back on, when the paradigm shifts against you. I’m not even sure what exactly I enjoy about it besides that it is comfortable and all that I know.

  9. “Gifted individuals face unique challenges. They don’t fit in. Can people develop normally without the company of their peers?

    Perhaps this is a factor which actively works against success in later life. Perhaps the stereotype “geeks” and “nerds” aren’t displaying inherent character traits but the effects of social deprivation.”

    It’s a tough world when you don’t have people around you with whom you can relate and understand. For a high-IQ person, it takes more effort than most people realize, to come down and talk at the level of the average person.

    I say this, not with pride, but with something closer to sorrow. I don’t think I was born with the intent to be seen as a geek. But when the only people you can relate with are much older than you, and the only people who seem to understand you are your professors, life can be lonely.

  10. I was personally delighted to read this article as I have always contended, seemingly without support, that IQ is not only unimportant in the real world, but that the tests can be fudged. My personal IQ, I found out was 130 – a meaningless number because it has not made me a millionaire or even good in business. What IS important is EIQ, AND plain old Chutzpah. My contention is though, that we DO need to somehow measure a person’s ability if there are a number of candidates for a job OR if we need to unearth some HIDDEN, LATENT talent. That is where the Analysis of Handwriting comes in – WHY in heaven’s name do people go there WHOLE lives not finding out what wonderful things their brain is telling them? The handwriting (BRAINWRITING) is the sacred key. It can pick up potential suicide, depression, integrity, sales ability, health issues (heart being a significant one) – so my plaintive cry is (the misquote Shakespeare a bit): THE ANSWER is NOT in the STARS Horatio, but in YOUR Hands. Give it a try – you will not be sorry. The alternative? – you will NEVER know what they are telling you…….

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