Intelligence (IQ) and work

I just stumbled across a very nice review article (by Linda Gottfredson in the Journal of Career Assessment, 2003) that provides an overview of the state-of-the art of cognitive ability assessment in vocational psychology. Vocational/career assessment is not my cup of tea, but I have high regard for the work of Gottfredson, a top scholar in the field of intelligence (see link to her web page under "IQ Scholars" section of blog). Below is the abstract, followed by a few featured conclusions.

Abstract

• Abilities are as important as interests in career choice and development. Reviving cognitive assessment in career counseling promises to help counselees better understand their career options and how to enhance their competitiveness for the ones they prefer. Nearly a century of research on human cognitive abilities and jobs’ aptitude demands in the U.S. economy reveals that the two domains are structured in essentially the same way. The author describes that common structure and how it can be used in assessing person-job match in terms of general ability level and ability profile. She also suggests ways of resolving various technical and professional questions, such as which cognitive abilities to assess, how to assess them, what the most useful aptitude-based occupational classification would be, and how to use cognitive assessments in a broader “reality-based exploration” process intended to expand people’s career opportunities.

What I particularly liked was Gottfredson's use of the Carroll tri-stratum model (aka, CHC theory) as the preferred model for understanding cognitive abilities in a vocational/career setting. The literature review is a nice overview of the major conclusions re: the effectiveness/utility of general, broad, and narrow cognitive abilities in vocational and career assessment research. A few interesting tidbits from her article related to utility of cognitive abilities as a function of breadth (stratum level) are noted below. There is much more to the article, so I'm only featuring a few points I found of interest as it relates to my interest and research in CHC theory. Gottfredson provides an excellent overview of the role of non-cognitive traits (personality, interests, emotional intelligence, etc.), but I'll let the reader decide if they want to read this information (space constraints of this blog format). In most cases the statements below are direct quotes.


Narrow abilities: The more specific or narrow an ability is, the more trainable and subject to shared family influences it seems to be. These facts are exceedingly important. They mean that there may be much scope for changing our narrower skills but that we must work with (rather than expect to change) our most general abilities.

General intellignece (g): The most general abilities are the best overall predictors of job performance... Meta-analyses have shown that the most general ability, g, predicts performance to some extent in all jobs In contrast, Stratum II (broad) abilities add little to the prediction of performance above and beyond g and then only in selected groups of jobs (e.g., spatial ability in certain technical and artistic jobs, speeded tests of clerical ability in clerical jobs). Stratum II abilities tend to predict job performance fairly well but generally only to the extent that they also reflect g...only that more general abilities are more broadly useful across the great variety of tasks and settings that we encounter in the workplace....low
general abilities greatly constrain the range of a person’s options in the workplace.

Broad abilities: Stratum II abilities are highly correlated among individuals of below average IQ (g), but the correlations weaken in higher IQ populations. In other words, brighter individuals tend to have more jagged Stratum II ability profiles. This suggests that profile shape may add more to the prediction of performance, beyond profile level, in higher IQ populations.....The broad cognitive abilities tend not to correlate much with either vocational interests or personality (e.g., Ackerman &Heggestad, 1997). The relative independence of the cognitive and noncognitive domains means that cognitive assessments provide useful information that cannot be obtained from the noncognitive inventories of personal traits. There are important points of overlap, as we shall see, but they are fairly localized.

Why cognitive tests are useful: Contrary to initial expectation, mental tests predict performance to some extent in all jobs, best in the most cognitively complex jobs, best when performance is measured objectively and relates to the most core technical duties of a job, and almost always better than any other type of predictor. Moreover, specifically tailored cognitive test batteries do little better than a lone measure of g. Tests of spatial and clerical aptitudes add slightly to variance predicted but only in certain groups of occupations. Assessments of less cognitive traits (temperament, interests, and the like) also add little to the prediction of core job performance, although they do outpredict g when organizational “citizenship” (helpful to coworkers, professional demeanor, and such) is the performance criterion. Psychomotor abilities and length of experience in a job predict performance best where g predicts it least, namely, in the lowest level, most routine jobs. The advantages of relatively greater experience fade at higher average levels of experience, but the advantages of higher g do not.

Broad and g relative importance: Thus, when we look across the full landscape of occupations, two features of ability requirements stand out. First, the single Stratum III ability, g, is relevant to all jobs but especially so in the most cognitively demanding and prestigious ones. Second, differences in ability profiles at the Stratum II level also matter, but they are secondary in importance. Their effects are smaller and more narrowly
targeted.

Figure 2 (Occupational aptitude patterns map) is a neat way to demonstrate the relations between cognitive ability and 12 clusters of work. Check it out. I love "big picture" summary charts and figures.

I'd have to examine the research studies reviewed by Gottfredson, but I wonder if the power of "g" may be overestimated in this literature due to the same type of methodological limitations that, for years, tended to suggest the same "g"-dominance in understanding school achievement. More recent g+specific abilities school achievement research which has used comprehensive measures of the major CHC abilities and employed SEM methods have suggested that more specific (broad or narrow abilities) are important "above and beyond" the influence of "g" and that the influence of "g" may be more of an indirect effect mediated via broad and narrow abilities. I'd like to see similarly designed studies in this field.

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