It is a common misconception online that pre-employment IQ testing is proscribed due to Griggs vs. Duke. This is false, as I epxlain in more detial here.
AFIK, no employer administers an actual IQ test, such as the Stanford-Binet or Wechsler Adult Intelligence Scale tests, as those are expensive and time-consuming to administer and typically must be proctored by a psychologist adhering to strict guidelines, but rather proxies that correlate highly with IQ are used, a major one being the ‘Wonderlic Contemporary Cognitive Ability Test (WPT),’ among others. Other proxies include SAT scores.
Requiring a college degree or a high school diploma, even if the degree is not directly applicable for the work the job entails (unlike how a medical degree or a law degree is directly applicable for practicing medicine or law ) can also be considered a proxy, but due to grade inflation and other factors, a weak one, which is why it is not uncommon for employers to both require a degree while still using the Wonderlic. So this pretty much means that anyone who passes this gauntlet of having a good Wonderlic score and a high GPA, can reasonably be assumed to be intelligent, even without an actual IQ score.
Same for the U.S. military, which administers a test called the ASVAB to all recruits, which like the Wonderlic, is considered a proxy for IQ. Recruits who fail to score above a certain threshold, usually 30, (which confers a score in the 30th percentile, or an IQ of roughly 83) are ineligible to enlist in any branch of the the U.S. military. The Coast Guard is considered to be the hardest to get into, requiring a minimum score of 40, which is still below the 50th percentile of general intelligence. As you can see, the military tends to be much less picker than most employers, and is why joining the military is often considered a ‘path to the middle class’ for millions of Americans.
So how common is pre-employment IQ screening? In spite of Griggs, a Google search and also Reddit, would seem to suggest it is very common, with hundreds of posts, threads, comments about having taken the Wonderlic or having to take it as a requirement of being hired. The official Wonderlic website says 70,000 employers use the test, notably the NFL which is the only sports league , afik, in the world that uses the test, which although has been a tradition in the NFL for half a century, is not factored highly in recruiting, nor is it predictive of success on the field.
Scanning through a trial test of the Wonderlic, the questions are easy and should be doable by anyone with a high school degree, yet you would be surprised by how many people are unable to perform even simple athematic or just basic reasoning. I remember I was working with someone and I sent him some cryptocurrency and he asked me how much it was in dollars. We’re literally talking a single multiplication (the price of the crypto times the quantity I sent him). This was not a communication gap or anything like that…the guy literally could not perform multiplication. This is why pre-employment testing exists.
However, the strict time limit imposed by the Wonderlic (WPT) test–just 12 minutes to answer 50 questions–ensures that the results follow a normal distribution (the so-called Bell Curve), much like a full-scale IQ test, with scores above 45 correct or fewer than 5 correct, being very rare. Despite the WPT taking 12 minutes to complete, it has a very high correlation with full-scale IQ scores (WAIS).
Souce: Validity of the Wonderlic Personnel Test as a Brief Measure of Intelligence in Individuals Referred for Evaluation of Head Injury:
Comparisons of the WPT to the Wechsler Adult Intelligence Scale (WAIS; Wechsler,1955) revealed correlations ranging from .85 to .93 and statistically nonsignificant differences between mean WPT and mean WAIS scores.
studies found the clinical utility of the WPT to be good, with 81 to 94% of WPT scores falling within 10 points of the gold standard WAIS FSIQ. The availability of published Wonderlicto-WAIS IQ conversion tables (Dodrill, 1980, 1981) made the WPT even simpler to apply
This is pretty amazing given how the WPT is so short. Even before writing this article I didn’t know the correlation was so high. But part of the reason IQ tests ‘work’ is that each section of of an IQ test is highly correlated with the other sections. The WPT happens to test for verbal and numerical reasoning, but these are highly correlated with other sub-tests such as spatial reasoning and digital recall.
This is a testament to the success , reliability, reproducibility, and validity of IQ, compared to other aspects of human psychology.