Average IQ does differ by profession. In the classic studies, accountants, lawyers, engineers, physicians and scientists have the highest average scores, and jobs involving routine manual work have the lowest. But the spread inside every occupation is wide, the ranges overlap heavily, and the clearest pattern is that complex jobs have a higher minimum score, while bright people turn up in every line of work.
That pattern matters more than any single average. A list that says "lawyers: 120" hides the fact that some lawyers score near the population mean and many people in jobs with lower averages score well above typical lawyers.
Where the data on IQ by occupation comes from
Large, representative datasets that link tested ability to adult occupation are rare. Two sources come up again and again.
The Army General Classification Test, 1940s
During World War II the US Army gave the Army General Classification Test (AGCT) to millions of recruits. Thomas and Margaret Harrell (1945) tabulated the scores of many thousands of white enlisted men by the civilian job each man had held before the war, covering dozens of occupations.
The ordering looks familiar. Accountants, lawyers and engineers had median scores in the high 120s; teamsters, miners and farmhands had medians around 90. The striking part is the ranges. In the lower-median occupations the top scorers reached the 140s, above the typical accountant, while the lowest scorers among accountants and lawyers were well below the group medians of their professions.
Two cautions apply. The AGCT used a standard-score scale with a standard deviation of 20, not the 15 used by modern IQ tests, so its numbers are not directly IQ points. And the sample was 1940s white enlisted men, with the educational opportunities of that era, which shaped who could enter which occupation.
The Wisconsin Longitudinal Study
The Wisconsin Longitudinal Study has followed a sample of about ten thousand people who graduated from Wisconsin high schools in 1957 and took the Henmon-Nelson test of mental ability in high school. Sociologist Robert Hauser (2002) used it to plot the full distribution of adolescent test scores within each adult occupation.
His analysis showed that there is a great deal of variation within occupations, and the differences between occupations are concentrated at the bottom of the range. In high-status professions few people had low scores, but the top of the distribution varied much less from job to job. The pattern is often summarized as a rising floor rather than a rising ceiling.
The rising floor, explained
Why would complexity raise the minimum but not the maximum? The mechanism is mostly about gatekeeping.
- Training filters entry. Medical school, law school and engineering programs select on grades and admission tests, both of which correlate with general ability. Few people with low scores pass those filters.
- Nothing filters out high scorers. No rule keeps a high-ability person out of a trade, a farm or a small business. People choose jobs for many reasons: family, location, money, interest, opportunity, health and timing.
- Opportunity shapes the top. In 1940s data especially, many able people never had access to college. Their scores show up in occupations that did not require it.
The practical lesson is that knowing someone's job tells you a little about their likely test score, and knowing their score tells you little about their job.
How large are the differences between occupations?
A meta-analysis of longitudinal studies by Tarmo Strenze (2007) found that intelligence measured in youth correlates about 0.43 with the prestige of the occupation a person later holds. That is a real association, comparable in size to the link between parents' socioeconomic status and their children's occupations in the same review.
A correlation of 0.43 also means that IQ accounts for under a fifth of the variation in occupational level (0.43 squared is about 0.18). Most of what determines who ends up in which job lies elsewhere: education, family resources, personality, interests, local labor markets and luck.
Within a job, ability does predict performance, especially in complex work. Schmidt and Hunter (2004) reviewed decades of research showing that general mental ability predicts both the level of job people attain and how well they perform in training and on the job, with larger effects for more complex jobs. Later work suggests some of those classic estimates were too high; see cognitive ability tests in hiring for the revision.
A rough guide to occupations and complexity
Instead of a list of invented averages, here is the pattern the classic data supports. It describes where scores typically cluster in research samples, not who can or should do a job.
| Occupation group | Examples | What the data shows |
|---|---|---|
| Highly complex professional work | Physicians, lawyers, scientists, engineers, accountants | Highest averages; few low scorers; still a wide spread above the floor |
| Technical and managerial work | Technicians, teachers, nurses, managers, programmers | Above-average means; broad overlap with the groups above and below |
| Skilled trades and clerical work | Electricians, machinists, clerks, sales | Means near or a little above the population average; very wide ranges |
| Routine and manual work | Laborers, drivers, farmworkers | Lowest averages in the old data, yet a substantial minority score well above the population average |
If you see a precise figure such as "the average software engineer has an IQ of 128," ask where it came from. Most such numbers are recycled from the 1945 AGCT table (on a different scale, for occupations that have since changed), from small convenience samples, or from no source at all.
High-IQ jobs: what the label really means
"High-IQ jobs" usually refers to work with heavy demands on reasoning, learning speed and abstract problem-solving: medicine, law, research science, engineering, actuarial work, software architecture and senior strategy roles. Linda Gottfredson (1997) described this in terms of job complexity: the more novel, ambiguous and fast-changing the problems a job presents, the more general ability helps.
Three points keep the label honest:
- Ability is necessary but not sufficient. These professions also select heavily on persistence, years of training and the money to pay for it.
- Complexity exists across the job market. Diagnosing a fault in an industrial system, running a farm or managing a busy kitchen can be cognitively demanding, even though they never appear on "high-IQ jobs" lists.
- A high score does not obligate you to a profession. People with high scores are found in every occupation in the data, and many are satisfied there.
Choosing a career by cognitive strengths
A full IQ score is a summary of several abilities. Modern tests, organized around the Cattell–Horn–Carroll (CHC) model, report separate domains such as verbal reasoning, quantitative reasoning, visual-spatial reasoning, working memory and processing speed. Some people have a fairly even profile; others have marked peaks.
The research on career fit is clearer for interests than for ability profiles. Vocational interest measures, such as the Holland RIASEC framework used by many career counselors, predict which field people enter and stay in. Ability profiles add something: analyses of the large Project Talent sample by Wai, Lubinski and Benbow (2009) found that adolescents whose quantitative and spatial abilities stood out relative to their verbal ability were more likely to end up in STEM fields, while relative verbal strength pointed toward other fields. A sensible approach uses both.
- Strong quantitative and visual-spatial reasoning fits work with models, data, structures and machines: engineering, analytics, architecture, the trades that involve design or diagnostics.
- Strong verbal reasoning fits work built on reading, argument and explanation: law, teaching, writing, policy, much of management.
- Strong working memory and fluid reasoning help in fast-moving roles where you juggle information and solve unfamiliar problems.
STEM versus creative profiles
The idea of a "STEM brain" versus a "creative brain" is overstated. Creative and technical fields both draw on general ability, and creative achievement in science, design and the arts depends on deep domain knowledge built over years. What differs more is interest and the kind of feedback a field gives: engineering offers clear right answers, the arts offer open-ended ones. Your preferences on that point are often a better guide than a test score.
Changing careers: does IQ matter?
If you are considering a move into a more demanding field, the evidence suggests your test score is rarely the deciding factor. Credentials, the time and money to retrain, prior knowledge and network usually matter more. General ability helps most with learning new material quickly, which is a real advantage early in a career change. After that, much of its effect runs through the job knowledge you accumulate, so steady practice in the new field counts.
A practical approach is to test the new field directly: a course, a project or a few conversations with people doing the work will tell you more than any score. If you want a sense of your relative strengths across domains, you can take the free test; it reports an estimate of where you stand among our respondents and is meant for self-insight, not for career placement. For what such a score can and cannot tell you, see how to interpret your results and the different types of intelligence.