Perhaps the most comprehensive study of American Jewish IQ was a 1958 paper on 64 Yeshiva men (age 16 to 31; mean age 21.43). Author Boris M. Levinson states:

Our sample finally consisted of 64 subjects, classified as follows : (a) six senior Yeshiva High School students, (b) 31 Yeshiva College students, (c) 27 graduate students. Among them were four ordained rabbis. Every graduate student was an alumnus of Yeshiva College. The writer believes that the sample secured was fairly representative of the Yeshiva population…

Below are the scores of the sample on the original Wechsler Adult Intelligence Scale (WAIS). The 11 subtest scores are expressed on a scale where the average American scores 10 (SD = 3), and the verbal, performance, and full-scale IQs are expressed on a scale where the average American scores 100 (SD = 15). To convert scaled scores to IQ equivalents, just multiply by 5 and then add 50. Because the study, was submitted for publication in 1957 and the WAIS was standardized in 1953.5, there was a trivial Flynn effect I adjusted for.

Unfortunately, this study was restricted to the Yeshiva population who, despite their religiosity, are presumably more educated than the general Jewish American population. However if we assume Yeshiva young adults were somewhat equivalent to Jewish university students (which I suspect virtually almost all of them were or would become), then it’s possible to adjust their scores downward to estimate how the average Jewish American would have scored.

But first we need to know how the WAIS correlated with education among young adults in the 1950s, and fortunately David Wechsler published that data on page 251 of his book The Measurement and Appraisal of ADULT INTELLIGENCE Fourth Edition.

WAIS measuresCorrelation with education in 1952.5 (age 25-34) n=300
Information0.655
Comprehension0.511
Arithmetic0.490
Similarities0.522
Digit Span0.421
Vocabulary0.649
Digit Symbol0.590
Picture Completion0.441
Block Design0.397
Picture Arrangement0.476
Object Assembly0.349
Verbal Score0.662
Performance Score0.570
Total Score0.658

The next question that needs to be answered is how educated were Jewish university students in the 1950s, compared to the general U.S. Jewish population. According to Diana B. Turk of Jewish Women’s Archives,: “By 1960, sixty-three percent of Jewish men and women aged eighteen though twenty-four attended college” This suggests Jewish university students were half a standard deviation more educated than America’s average Jewish young adult.

On a scale where all Americans average IQ 100 (SD = 15) and scaled scores of 10 (SD = 3), if we crudely assume, that Jewish Americans have the same IQ standard deviation as American whites (SD = 14.5 and 2.9 respectively) and the same correlations with education as Americans as a whole, and further assuming a bivariate normal distribution, we can simply take the product of half the Jewish standard deviation and the correlation between IQ and education and subtract it from the median scores in the Yeshiva sample (adjusted for the Flynn effect) to get the general U.S. Jewish average.

This gives the following:

U.S. normsU.S. white norms
Information14.89
Comprehension15
Arithmetic13.15
Similarities11.93
Digit Span12.3
Vocabulary12.8
Digit Symbol10.88
Picture Completion11.1
Block Design10.28
Picture Arrangement9.2
Object Assembly8.3
Verbal IQ121120
Performance IQ9896
Full-scale IQ112110

My analysis suggests the average American Jew has a verbal IQ of 120 (white norms) and a Performance IQ of 96. Until a representative sample of Jewish Americans take a comprehensive test, it’s hard to know how accurate my estimate is.

Of course there have been such studies of Jewish school children, and because virtually everyone attends school in childhood, these are arguably more representative of the general Jewish population. After adjusting for the Flynn effect, Richard Lynn reported two such studies in Canada on page 117 of The Global Bell Curve:

Note that in the first study, spatial IQ refers to Wechsler performance IQ (though the two constructs are not identical )Averaging across both studies, the average verbal IQ is 115 (white norms)and the average “spatial IQ” is 102. This gives a verbal > spatial/performance IQ gap of 13 points (much smaller than the 24 point gap I estimated) however Lynn is citing childhood IQ, and Daniel Seligman notes in his book A Question of Intelligence:

Some studies show rising verbal scores as the Jewish children pass through school, but the reasons for this increase are unclear. Some scholars view it as a maturational change, that is, the group is genetically programmed to improve its already superior verbal skills with age.

Does Seligman speak from personal experience? Based on pro-rating the Wechsler scores he describes in his book, I estimated he has a verbal IQ of 146 (white norms) and a Performance IQ of 98!