A study was conducted to examine the factors influencing undergraduate women's likelihood of persistence in their majors, based on Kanter's theory that members of the numerical minority in any group experience role entrapment and performance pressure as a result of their underrepresentation. Interview data were obtained from a stratified, random sample of 636 female undergraduates that included a sampling of Black, Hispanic, Asian and Pacific Islander students. Findings included the following: (1) performance pressure had a statistically significant, negative impact on women's likelihood of persistence in their major; (2) role entrapment had the expected negative relationship to likelihood of persistence, but its effect was non-significant; (3) a curvilinear relationship was found between enrollment balance and likelihood of persistence in the undergraduate major; and (4) women in male-dominated majors, as well as those in female-dominated majors, were more likely to persist than women in majors where the enrollment was more balanced. Contains 31 references. (Author/KM)