Fewer women than men pursue careers in science, technology, engineering and mathematics (STEM), despite girls outperforming boys at school in the relevant subjects. According to the 'variability hypothesis', this over-representation of males is driven by gender differences in variance; greater male variability leads to greater numbers of men who exceed the performance threshold. Here, we use recent meta-analytic advances to compare gender differences in academic grades from over 1.6 million students. In line with previous studies we find strong evidence for lower variation among girls than boys, and of higher average grades for girls. However, the gender differences in both mean and variance of grades are smaller in STEM than non-STEM subjects, suggesting that greater variability is insufficient to explain male over-representation in STEM. Simulations of these differences suggest the top 10% of a class contains equal numbers of girls and boys in STEM, but more girls in non-STEM subjects.

中文翻译：

---

学术成绩个体差异的性别差异不符合 STEM 的预期模式。

尽管女孩在学校相关科目的表现优于男孩，但从事科学、技术、工程和数学 (STEM) 职业的女性人数少于男性。根据“变异假说”，男性比例过高是由方差中的性别差异造成的；更大的男性变异性导致更多的男性超过绩效阈值。在这里，我们利用最新的元分析进展来比较超过 160 万学生的学业成绩的性别差异。与之前的研究一致，我们发现强有力的证据表明，女孩的差异低于男孩，并且女孩的平均成绩较高。然而，STEM 科目成绩均值和方差的性别差异均小于非 STEM 科目，这表明较大的变异性不足以解释 STEM 中男性比例过高的原因。对这些差异的模拟表明，班级中前 10% 的 STEM 科目中女生和男生的数量相等，但非 STEM 科目中的女生较多。