The Annoyingly Indeterminate Effect of Sex Differences

56 Pages Posted: 10 Mar 2009 Last revised: 27 Sep 2010

Date Written: August 5, 2009


At present, men and women have different distributions of certain aptitudes and personality traits. A growing body of research suggests that some of these differences have some biological basis, although these distribution differences do not always conform neatly to traditional stereotypes and cultural factors also contribute.

A heritable basis for difference, however, has frustratingly indeterminate implications. It suggests that some occupational segregation is not caused by discrimination. At the same time, a statistical aptitude or temperament difference will almost inevitably cause discrimination in professions that make use of that aptitude or temperament. This implication is supported by empirical evidence about the continued existence of discrimination from disparate sources, including labor market data and experimental laboratory studies in both economics and psychology.

The offsetting effects of difference and statistical discrimination make it extremely difficult to predict the degree of occupational segregation in a non-discriminatory world. To complicate matters further, there is no simple relation between the size of ability differences and the efficient degree of occupational segregation. The principle of comparative advantage suggests that even small ability differences might produce large degrees of occupational segregation. Conversely, high demand in a sector using skills that favor one sex may draw the other sex into sectors in which they have an absolute disadvantage.

Ability distribution differences create tremendous challenges for anti-discrimination policy. Liability rules based on current labor market representation are of minimal use, since the labor market reflects existing discrimination. Though perhaps useful in the short term, long-term numerical targets are problematic: target goals are extremely difficult to set, and would need to become a permanent institution. Moreover, numerical targets may create unintended problems for women. Men have historically dominated even fields in which women have an advantage. A target goal of equal representation would prevent women from attaining majority status in these fields. Closer scrutiny of employer practices holds promise as an alternative to numerically based theories.

Earlier versions of this paper were circulated with the title "The Paradox of Statistical Discrimination"

Keywords: Occupational Segregation, Discrimination, Sex Differences

Suggested Citation

Weiss, Deborah M., The Annoyingly Indeterminate Effect of Sex Differences (August 5, 2009). U of Texas Law, Law and Econ Research Paper No. 151. Available at SSRN: or

Deborah M. Weiss (Contact Author)

Northwestern University School of Law ( email )

600 North Lake Shore Drive
Chicago, IL 60601
United States

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