A sex difference by item difficulty interaction in multiple-choice mathematics items administered to national probability samples

A 1998 study by Bielinski and Davison reported a sex difference by item difficulty interaction in which easy items tended to be easier for females than males, and hard items tended to be harder for females than males. To extend their research to nationally representative samples of students, this study used math achievement data from the 1992 NAEP, the TIMSS, and the NELS: 88. The data included students in grades 4, 8, 10, and 12. The interaction was assessed by correlating the item difficulty difference (b_male - b_female) with item difficulty computed on the combined male/female sample. Using only the multiple-choice mathematics items, the predicted negative correlation was found for all eight populations and was significant in five. An argument is made that this phenomenon may help explain the greater variability in math achievement among males as compared to females and the emergence of higher performance of males in late adolescence.