Marcia Linn, a University of California, Berkeley, professor of education known for exploring the teaching and learning of science and their connection to gender, is offering proof once again that girls’ math abilities are just as good as boys’.

But Linn and her fellow researchers note in their global study, reported in the latest issue of American Psychological Association’s Psychological Bulletin, that while there are only small differences, on average, between girls’ and boys’ math abilities, the gaps vary widely from country to country. For girls to perform as well as boys on math tests, the researchers found that they need equal access to education, encouragement to do well in math and female role models in math-oriented careers.

The study was funded by the National Science Foundation. It looked at results released in 2003 of two key math tests — one focusing on basic math knowledge and the other on students’ ability to use math skills in the real world — that were administered to nearly half a million boys and girls between the ages of 14 and 16 in 69 countries. The tests were the Trends in International Mathematics and Science Study and the Programme for International Student Assessment.

Working with Nicole Else-Quest, a psychology professor at Villanova University in Pennsylvania, and Janet Shibley Hyde at the University of Wisconsin, Madison, Linn found that nations with more women in scientific research show smaller gender differences in findings of self-confidence, valuing math, motivation, math anxiety, and related issues.

Linn says math success depends on a complex array of social, economic, and personal factors, and that the study reveals clear benefits of equitable access to education and to careers requiring mathematics. It also shows a need for country- and curriculum-specific research to develop policies that promote equity in educational achievement and careers, she says.

Linn notes that, despite similar performances by boys and girls on tests of mathematical reasoning, in most countries boys are more self-confident than girls about their math skills. This finding aligns, she says, with stereotypes of female inferiority in mathematics and could account for the disparities in participation in mathematics and science careers.

Linn says she is surprised that there were no overall differences between boys’ and girls’ performance on geometry problems. She speculates that the trend towards smaller gender differences in spatial reasoning “may be due in part to greater access to graphing calculators, computer games and other visualizations of spatial relationships.”

The full report is online at the American Psychological Association’s Web site.

Linn directs one of the 13 National Science Foundation-funded Technology-enhanced Learning in Science centers, and it is based at UC Berkeley’s Graduate School of Education. She is the author of several books on science education.