Female student performance in high-stakes biology exams

Phys.org reported on a new study a couple of weeks ago:

A new study of students in introductory biology courses finds that women overall performed worse than men on high-stakes exams but better on other types of assessments, such as lab work and written assignments. The study also shows that the anxiety of taking an exam has a more significant impact on women's grades than it does for men.

 "It was striking," said Shima Salehi, a doctoral student at Stanford Graduate School of Education and one of the study's two lead authors. "We found that these types of exams disadvantage women because of the stronger effect that test anxiety has on women's performance."

The original study is available here (open access), published in the online journal PLoS ONE. The authors were Cissy Ballen (University of Minnesota), Shima Salehi (Stanford), and Sehoya Cotner (University of Minnesota). The results are based partly on data from 1205 first-year biology students over ten sections, with the results on test anxiety (and 'interest in course content') based on survey data from 372 students over three sections. In the paper, the key research questions were:

1) What is the extent of the gender gap in incoming academic preparation among students? 2) What is the extent of the gender gap in exam grades and non-exam grades? 3) Do women and men report different levels of test anxiety and interest in science? 4) Do these two affective factors influence performance outcomes in undergraduate biology courses?

The authors found that there was a significant gender gap in academic preparation among students, with ACT (American College Test) scores on average about 0.28 standard deviations lower for female than for male students. There was also a difference in exam grades between female and male students, of 0.15 standard deviations. However, to me the key result is:

When we included incoming ACT score in the model as a fixed effect, the gender gap in exam performance disappeared...

In other words, the performance gap in exams between female and male students was almost entirely explained by differences in student quality (as measured by the ACT score). There was no need for the authors to dig into text anxiety or interest in course content, especially given that the results they present based on their mediation analysis actually don't show anything because the combined paths are not statistically significant. Female students did worse because they were worse students, not because of some gender bias or because of test anxiety.

Or maybe not. I noticed that at one point in the paper, the authors note that the exam grades were "multiple-choice exam grades", which implies (to me) that the exams were wholly multiple choice. And we know based on past research that female students have a disadvantage in multiple choice questions. In the Phys.org article, one of the authors is quoted as saying:

We want to figure out what kind of instructional methods will ensure that everyone can navigate successfully through these courses and have a wider range of career options.

Worry less about the instructional methods. Ditch the multiple choice in your exams, or replace them with a mixture of multiple choice and constructed response. Your female students will appreciate it.