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A new study shows that first-grade teachers consistently rate girls’ math ability below boys’ — even when they have the same achievement level and learning style. The study out today in the journal AERA Open from researchers at New York University and the University of Illinois at Urbana-Champaign seems to represent a setback for gender equity in math. A widely reported 2008 study found that girls score as well as boys do on standardized state math tests. But the latest study suggests that early in their math education, many girls run into a teacher who perceives them as being worse at the subject than they are — which could discourage some of them from heading down a path that could lead to a career in math, science or engineering.

The study tapped into research following 7,507 children nationwide from kindergarten through first grade, starting in 2010. Teachers in the study were asked to rate their students on their math ability. The harsh ratings didn’t start right away. In kindergarten, girls and boys were rated about equally, when controlling for their scores on independent assessments, as well as their age, socioeconomic status and learning style. But in first grade, girls were rated lower, on average, across the achievement spectrum.

That’s consistent with the researchers’ analysis of students in a 1998 wave that followed them through third grade. Then, too, the kindergartners appeared to be rated fairly, but by first grade boys got an edge, which they retained through third grade. So progress in gender equity in math appears to have stalled in grade school.