Duke TIP Research Team Announces Key Findings of 30-Year Study
Duke University Talent Identification Program
June 2010

One factor in the debate surrounding the underrepresentation of women in science technology, engineering and mathematics (STEM) involves male–female mathematical ability differences in the extreme right tail (top 1% in ability). This article is about a study that provides male–female ability ratios from over 1.6 million 7th grade students in the right tail (top 5% in ability) across 30 years (1981–2010) using multiple measures of math, verbal, and writing ability and science reasoning from the SAT and ACT.

The Duke Talent Identification Program announces key research findings in the area of sex differences in cognitive abilities, in particular mathematical ability and science reasoning. A recent study, “Sex differences in the right tail of cognitive abilities: A 30 year examination,” conducted by four Duke TIP researchers, including Executive Director and Professor of Psychology Martha Putallaz, Ph.D., considers standardized test scores of over 1.6 million 7th graders across three decades. The study findings hold potential implications for the underrepresentation of women in science, technology, engineering, and mathematics (STEM) fields.

Since 1981, TIP has conducted an annual Talent Search, whereby 7th graders take the SAT or ACT—generally given to high school juniors—to assess their academic ability. Using these SAT and ACT scores, TIP’s team of researchers, including Jonathan Wai, Megan Cacchio, Martha Putallaz, and Matthew C. Makel, were able to adequately capture the individual differences in ability in the highest-scoring children.

The team found that the gender gap between 7th grade boys and girls in mathematical ability is substantially lower than it was 30 years ago, but that there continues to be a gap in mathematical ability. Additionally there is still a gap in what the researchers suggest should now be considered a new factor in the debate—science reasoning.

"Our primary goal is to inform the debate with much needed data which is consistent with multiple explanatory points of view."

The TIP researchers examined the top 5% of ability (the right tail), but primarily focused on the top 0.01 percentile of these students: those 7th graders who scored 700 or above on the SAT-Math portion or the equivalent on the ACT-Math and ACT-Science portions (see Figure 1). They found that in the early 1980’s there were roughly thirteen males to every female scoring 700 or above on the SAT-Math, and ten years later, in the early 1990’s, there were roughly four males to every female, this ratio drop being likely due to sociocultural factors (such as academic encouragement and mathematical instruction of females). However, the ratio has not substantially changed since the early 1990’s. Additionally, for the last 20 years, the male-female ratios on the ACT-Math and the ACT-Science have also remained fairly stable at about three males to every female.

Although the researchers found that males are more highly represented on measures of math ability and science reasoning, they also found that females are more highly represented on some measures of verbal and writing ability. However, because the male-female ratios on math ability and science reasoning have been fairly stable for the last 20 years, they conclude that “sex differences in abilities in the extreme right tail should not be dismissed as no longer part of the explanation for the dearth of women in math-intensive fields of science.”

These findings likely help partly explain the scarcity of women in high-level STEM careers and possibly inform some current policy debates, as many STEM innovators are likely later drawn from this population. Additionally, prior research has linked ability differences within this population to later high-level STEM achievement, such as earning a Ph.D., publication, patent, or even tenure at a top university.

Jonathan Wai, Ph.D., the lead researcher on the team, says of the findings, “Our primary goal is to inform the debate with much needed data, which is consistent with multiple explanatory points of view. It is important to highlight that among the many interlocking factors in the ever-changing ‘equation of explanation,’ cognitive abilities are only one factor. Male-female differences in preferences of academic and career pursuit, for example, are also likely important and we cannot rule out potential biases and barriers. We also cannot predict whether the math and science ratios will remain stable or change in the future, thus future examinations will be needed, perhaps in the next 30 years.”

The full study (https://tip.duke.edu/sites/default/files/intelligence_article_0.pdf) , is slated to be published in a forthcoming issue of the journal Intelligence.

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