The records of graduates of Iowa high schools who entered the University of Iowa as freshmen in the fall of 1977 were secured in cooperation with the Iowa Testing Program. Test scores for grades 4, 6, and 8 on the Iowa Tests of Basic Skills and for grade 11 on the Iowa Tests of Educational Development were obtained for all students whose scores could be located in the records of the Iowa Testing Program. The data were grouped into five test areas: vocabulary, reading, language or expression, work-study or sources of information, and mathematics. The performance of males and females in these five areas was compared across grades. In this group of students who later entered college, girls consistently outscored boys in language or expression across the grades examined, but the boys' mean score was significantly higher than the girls' mean in mathematics at grade 11. The girls' mean score in mathematics was higher initially, but by sixth grade boys scored higher in mathematics on the average and continued to score higher than girls in grades 8 and 11. In the other three areas boys and girls scored similarly. (Author)