What is the relationship between IQ and job performance?
- Nikola Erceg, Spencer Greenberg, and Beleń Cobeta
- Sep 21, 2024
- 2 min read
Updated: 7 days ago
Note: This is a section of a longer article. To go to the start, click here.
IQ is positively related to job performance. We measured job performance by asking our participants to rate themselves on a series of statements such as “I have been told by a boss before that I need to improve at work.”, “I regularly exceed expectations with the quality of my work.”, “I don't always try very hard to do an exceptional job at work.”, “I have had times in the last three years where I was a bad employee.” or “I always get my work done on time.” (31 such statements in total) and summed up their responses to get the total “good employee” score. Here, a higher score means that the participant rated him/herself to be a better employee.
When correlating this score to IQ, we obtained a correlation of r = 0.18 (n = 686). However, in additional analyses we uncovered something interesting: the relationship between IQ and good-employee score was not linear. It seems that IQ predicted job performance up to a certain IQ level, after which it ceased to be a good predictor of job performance. We divided our sample into three separate groups: low IQ group (IQ < 92), average IQ group (>=92 & <= 108) and high IQ group (IQ > 108) and correlated IQ to a good-employee score in each of these groups. Only in the lower-IQ group was IQ a significant predictor of good-employee score and this correlation was quite large (r = 0.46). In other groups, IQ was practically unrelated to good-employee score. This means that IQ was a potent predictor of job performance only at lower levels of IQ, but not for people with average or high IQ. Here is a graph that illustrates this non-linear relationship between IQ and good-employee score.

What do the other studies say?
First, it is important to note that studies generally show that IQ has a linear effect on various outcomes (e.g., Brown et al., 2021) and in this sense our study does not agree with the literature. However, regarding the question of whether IQ predicts job performance, our results align with general consensus in literature that IQ does positively predict job performance. Earlier meta-analysis on this by Schmidt & Hunter (1988) found a very large meta-analytical correlation between IQ and job performance (r = 0.51). However, a more recent meta analysis by Sackett et al. (2022) that revisited these estimates and corrected them by using more realistic statistical procedures for effect-size estimation estimated this correlation to be r = 0.31.
Takeaways
IQ predicts better self-reported job performance, but only in a subsample of participants with IQ lower than average.
If you'd like to read the full report, of which this is a section, as one long PDF, you can download it here.
And if you'd like to understand where your intellectual strengths and weaknesses lie, try the cognitive assessment tool that we developed out of this research: