This manuscript is a very though and complete rebuttal to the claim of the Richardson & Norgate paper in 2014. Richardson & Norgate’s main claim is that the well-established correlation between IQ and job performance is rather dubious and treated with much caution than is currently accepted among scholars. The reason for this contention consists of four main points:
- Construct validity of IQ is not solid.
- Job performance is measured by supervisor ratings, which is very inaccurate and prone to various prejudice and bias
- Meta-analysis is not a panacea and a strong conclusion cannot be obtained not as firmly as widely accepted.
- Non-cognitive factors are supposed to play more important roles, such as motivation, anxiety, emotional intelligence, etc.
In other words, Richardson and Norgate’s strategy is casting doubts on the concepts of IQ, the objectivity of job-performance ratings, reliability of meta-analysis, and finally suggest some other factors affecting job performance.
While this reviewer is not an expert on this IQ job performance literature and methodology of meta-analysis, none of Richardson & Norgate’s arguments sound persuasive enough to cast doubt on the well-established results from Hunter and Hunter (1984), Hunter (1986) among others. Authors carefully address these fallacies in the above reasonings in the manuscript with much wider relevant literature coverage and more rigorous logic.
Especially, this reviewer personally found that the suggestion of Emotional Intelligence as a relevant factor of job performance instead of IQ sounds like an amateur or journalist since EQ has long proven to be a mere mixture index derived from IQ and some personality traits in academia.
The manuscript is well-written at this point. Let me just point out two comments and two more suggestions of somewhat relevant literature on this topic.
1. P.20. About the description “. However, a more telling reason why Richardson & Norgate are incorrect about this is that conscientiousness, the willingness to do tasks thoroughly, actually has greater validity in lower complexity jobs, as shown by Le et al. (2010) and further discussed by Wilmot & Ones (2019)”.
Le et al (2010) actually confirmed their hypothesis that “: The level of Conscientiousness at which its relationship with task performance disappears (i.e., the inflection point) is determined by job complexity such that the inflection point for more complex jobs occurs at higher levels of Conscientiousness than the inflection point for less complex jobs”. This result is shown by figure1 in their paper and apparently, conscientiousness plays a more important role in more complex jobs. Please double-check the paper.
2. Wilmot & Ones’ (2019) paper on PNAS is missing in the reference section.
3. In Economics literature, IQ has been shown to be more important for income than the year of education. Altonji & Pierret (2001) estimate that 1 SD difference of the year of education have a 12% of annual return when a person gets a job. However, this return rate declines steadily to zero and instead, IQ becomes a more important factor, which shows a 13% annual return after 13 years of work experience.
4. It is widely known that 1 IQ point leads to a 1-3% increase in income (e.g., 2.5% by Dalliard, 2016; 3.1% by Jencks,1972; 1.4% by Zax & Rees, 2002,). Also, IQ and income are reported to correlate to some degree (e.g., 0.37 by Dalliard, 2016; 0.39 by Nyborg and Jensen, 2001; 0.297 by Zagorsky, 2007). There are certainly numerous papers of this kind out there. Given that these data are based not on a specific occupation but on all kinds of occupations in the real world, it is highly unlikely that IQ is not so much correlated with job performance.
Altonji, J. & Pierret, C. R., 2001, Employer Learning and Statistical Discrimination, Quarterly Journal of Economics, 116, 313-350.
Dalliard, IQ and Permanent Income: Sizing Up the “IQ Paradox”. Human Varieties, Jan. 31, 2016. https://humanvarieties.org/2016/01/31/iq-and-permanent-income-sizing-up-the-iq-paradox/
Jencks, S., 1972, Inequality, Penguin.
Nyborg, H. & Jensen, A. R. (2001), Occupation and income related to psychometrics. Intelligence 29, 45-55
Zagorsky, J. L. Do you have to be smart to be rich? The impact of IQ on wealth, income and financial distress. Intelligence (2007), doi:10.1016/j.intell.2007.02.003.
Zax, J.S. & Reese, D.I. 2002, IQ, Academic Performance, Environment, and Earning. The Review of Economics and Statistics,84,4,600-616.