  We present results of a combined study from three UK universities where we
investigate the existence and persistence of a performance gender gap in
conceptual understanding of Newtonian mechanics. Using the Force Concept
Inventory, we find that students at all three universities exhibit a
statistically significant gender gap, with males outperforming females. This
gap is narrowed but not eliminated after instruction, using a variety of
instructional approaches. Furthermore, we find that before instruction the
quartile with the lowest performance on the diagnostic instrument comprises a
disproportionately high fraction (~50%) of the total female cohort. The
majority of these students remain in the lowest-performing quartile
post-instruction. Analysis of responses to individual items shows that male
students outperform female students on practically all items on the instrument.
Comparing the performance of the same group of students on end-of-course
examinations, we find no statistically significant gender gaps.
