TEXTBOOKS are often contentious. In economics, most of the debate has been about how well the models they contain describe reality. Following the presentation of new research by Betsey Stevenson and Hanna Zlotnick, both at the University of Michigan, a new controversy is likely to open up, focused on the people that authors of American textbooks use as examples. The authors found that the gender mix in these vignettes consistently misrepresents the actual proportions found in the United States.

Ms Stevenson and Ms Zlotnick pored through eight leading textbooks on the principles of economics. Every time a person was mentioned, they recorded that individual’s gender and occupation. Some of the examples were taken from history, such as a president or a mayor making a policy decision, or a famous athlete advertising a product. Others were fictional or composite, like a farmer pondering how many bushels of wheat to sell at a given price.

All told, the researchers found more than 2,800 mentions. A striking three-quarters were of men. The most obvious reason is that nearly a third of this group were economists, a profession historically dominated by men. (Elinor Ostrom is the single woman among the 79 winners of the Nobel Prize in economics.) A large share of the remaining identifiable people mentioned are policymakers and business leaders, roles in which men have also predominated.

Nonetheless, the proportions of men found in the textbooks vastly exceed those observed in reality. For example, in America women owned 36% of businesses in 2012, and since 2008 they have comprised about a quarter of chief executives. In the books, however, just 6% of the real-world business leaders were female. A third of the policymakers appointed by Barack Obama were women, and one in five mayors in America is a woman. In the textbooks, however, women’s share in policy roles is a paltry 7% (and just as low if presidents and Federal Reserve chairs are excluded from the count).

Even among made-up and ordinary people featured on the textbooks’ pages, men outnumber women by a large margin. In the fictitious examples, men do most of the analysis and decision-making. Accordingly, they are much more likely than women to be featured in a business or policy setting. Women, on the other hand, are more likely to be featured in education, entertainment and domestic roles.

Such reliance on age-old gender stereotypes may help to perpetuate the wide gender imbalance found among economics graduates—as well as those in workplaces and households. One recent survey found that two-thirds of instructors who teach introductory economics think that students learn primarily by way of example.