Research in the past decade suggests that persistent gender gaps in ma
th achievement may be rooted in gender differences in math self-concep
t. Yet, limited research exists on how students' math self-concept dev
elops, and whether this differs between men and women. Using a sample
of 8,997 women and 6,053 men, this study examines the factors associat
ed with the development of women's and men's mathematical self-concept
during college. Findings reveal a number of student background charac
teristics and college environments and experiences that contribute to
an overall decline in math self-concept during college, and show how c
ollege reinforces the gender gap in math confidence. Additionally, in
an attempt to answer the perennial question of whether it is ''better
to be a big frog in a small pond or a small frog in a big pond,'' the
study pays special attention to the relationship between institutional
selectivity and math self-concept. Although institutional selectivity
is correlated with declines in math self-concept, results show that s
pecific aspects of selective environments, rather than selectivity its
elf, are more important predictors of math self-concept.