Professor Paola Sapienza  Photo © Nathan Mandell

Prof. Paola Sapienza: inequality adds up to math gender gap

The gender gap in math perceived to exist between girls and boys has long been contested. New research published in the journal Science adds clarity to the debate and demonstrates that girls perform better in mathematics in more gender-equal societies — in some cases besting male peers.

The research, led in part by Kellogg School Associate Professor of Finance Paola Sapienza, sought to address the issue of whether social and cultural factors influence women's success in math and science. Sapienza and her colleagues Luigi Guiso (Instituto Universitario Europeo) and Ferdinando Monte and Luigi Zingales (University of Chicago), investigated whether a global gender gap exists in math so that they could understand the relative importance of biology and culture on the development of basic mental attributes that are valuable for conducting math and science.

"The so-called gender gap in math skills seems to be at least partially correlated to environmental factors," Sapienza said. "The gap doesn't exist in countries in which men and women have access to similar resources and opportunities."

In search of bridges to span the math gender gap, Sapienza and her colleagues analyzed data from more than 276,000 children in 40 countries. The large number of subjects and broad range of social systems represented were keys to the study's validity. Each child took the 2003 Organisation for Economic Co-operation and Development Programme for International Student Assessment (PISA), a standardized assessment of math, reading, science and problem-solving ability.

Based on the PISA analysis, Sapienza and her co-researchers determined that while the global pattern shows boys tended to outperform girls in math (on average, girls score 10.5 points lower than boys), this advantage was not always the case. In a few countries, including Iceland, Sweden and Norway, girls scored as well as boys or better.

Sapienza and colleagues examined social features that might explain the variance across countries. The scholars used four tools to measure how well women were integrated into each society compared with men. These tools were the 2006 Gender Gap Index (GGI) developed by the World Economic Forum (WEF); the World Values Survey; the percentage of women aged 15 or older who are eligible to work in each country's labor force; and the WEF political empowerment index, which measures the representation of women in government.

Sapienza's team found that, in more gender-equal societies, the gender gap in math disappears. For example, the math gender gap almost disappeared in Sweden (GGI = 0.81), while girls scored 23 points below boys in math in Turkey (GGI = 0.59). Not only did average girls' scores improve as equality improved, but the number of girls reaching the highest levels of performance also increased.

Math and science rates for girls in the U.S., which ranks 23rd on the GCI scale with a score of 0.7, fell in the middle of the pack. On average, U.S. girls score almost 10 points lower than U.S. boys in mathematics, which is around the average for all countries analyzed in the study.

The research also found a striking gender gap in reading skills. In every country girls perform better than boys in reading. In more gender-equal societies, the girls' advantage in reading over boys increases further. On average, girls have reading scores that are 32.7 points higher than those of boys (6.6 percent higher than the mean average score for boys). In Turkey, this amounts to 25.1 points higher and in Iceland, girls score 61.0 points higher.

Said Sapienza, "Our research indicates that in more gender-equal societies, girls will gain an absolute advantage relative to boys."

MORE INFORMATION : The full study is published in the May 30, 2008, issue of Science. Additional details about this study is also available at Kellogg Insight, the Kellogg School's Web-based research portal: insight.kellogg.northwestern.edu.