Commenter caffeine withdrawals writes:

You should do a post on NFL Wonderlic test scores, PP. And also come up with a Wonderlic-IQ conversion. Curious to see what you think the ceiling is.

The first thing I found was this:

An economical method for the evaluation of general intelligence in adults.

Carl B. Dodrill
Published 1981 in Journal of consulting and clinical psychology

Apparently these IQs were largely derived from very old data. Dodrill (1981) writes:

By using the detailed information on Wonderlic’s (1973) sample of 251,253 job applicants, Wonderlic raw scores were first converted to IQ scores having a mean of 100 and a standard deviation of 15 to conform to the distribution of WAIS Full Scale IQs. A preliminary IQ conversion table was set up… First of all, the Wonderlic IQ scores were low in comparison with the WAIS Full Scale IQ when the latter was about 90 or more. Corrections were therefore made in the IQ conversion table. Second, it was noted that there was no correction for age, so Wonderlic’s (1973) suggested corrections for various age groupings were followed. The result of these two types of corrections constituted the final IQ conversion table (Table 1).

Unfortunately, Dodril should not have corrected the Wonderlic scores because they were low compared to the WAIS. The WAIS was normed circa 1953 and the Wonderlic norms were from 1973, so people taking both tests in 1981 would be expected to score higher on the former than the latter, but no one knew about the Flynn effect in those days so it’s understandable.

However I found a paper by Arthur Jensen stating that in a nationally representative sample taking form IV of the Wonderlic Personnel Test (circa 1972?) whites had a mean of 23.32 with a standard deviation of 7.5. So using white norms (which were also used by the original WAIS):

IQ = [(wonderlic score – 23.32)/7.5][15] + 100

So assuming raw scores are normally distributed, the test’s ceiling should have been IQ 153 for a perfect 50/50 and the test’s floor should have been IQ 53 for 0/50. One might even add the age bonuses suggested in table 1 and say that a 60-year-old who scored 50/50 actually scored 55, so she would have an IQ of 163!

However my formula is based on circa 1972 norms and may not give valid IQs for people today. If this data can be trusted, the scores of Quarterbacks seem to be improving rapidly. A regression line predicting Wonderlic score as a function of year suggests that at least among QBs, raw scores have been increasing by 0.35 points per year. Either this test is extremely sensitive to the Flynn effect, or they’re recruiting from smarter demographics, or they’re using an easier version of the test, or cheating/test prep/lying/selective disclosure is increasing.